How to find research summary in earth and space sciences - ACT Science
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Scientists studying historical trends in climate change have a number of tools at their disposal. One method of analyzing paleoclimate data involves the use of fossilized pollen spores embedded in sediment. Pollen spores are specific to the plant that produced them. Because the spores are resilient and are widely-distributed by wind, they provide a snapshot of the vegetation that was widespread at a particular point in time. By identifying the age of a sample and the composition of the various spores, scientists can identify the prominent vegetation and use this information to gain insight into the climate at the time the spores were deposited.
Scientists took sediment samples from various depths of a lakebed. They found that five types of pollen spores make up the majority of spore deposits in each sample. In Table 1, plants are listed along with the respective temperature ranges and levels of precipitation for the areas in which they are commonly found. Table 2 shows the composition of the assortment of spores in each of the four samples taken by the scientists.
If true, which of the following could serve as counter-evidence to the information provided in the passage?
Scientists studying historical trends in climate change have a number of tools at their disposal. One method of analyzing paleoclimate data involves the use of fossilized pollen spores embedded in sediment. Pollen spores are specific to the plant that produced them. Because the spores are resilient and are widely-distributed by wind, they provide a snapshot of the vegetation that was widespread at a particular point in time. By identifying the age of a sample and the composition of the various spores, scientists can identify the prominent vegetation and use this information to gain insight into the climate at the time the spores were deposited.
Scientists took sediment samples from various depths of a lakebed. They found that five types of pollen spores make up the majority of spore deposits in each sample. In Table 1, plants are listed along with the respective temperature ranges and levels of precipitation for the areas in which they are commonly found. Table 2 shows the composition of the assortment of spores in each of the four samples taken by the scientists.
If true, which of the following could serve as counter-evidence to the information provided in the passage?
The passage states that spore counts are representative of the vegetation population at the time the pollen was deposited. If large differences in pollen production and dispersion are not accounted for, the percent concentration of pollen spores will not function as a representation of plant concentration in an area.
The method of selecting sample depth and the specific size/shape of pollen grains are not critical to the study's main idea.
Because the study gives no interpretation of the spore concentration data, changing the temperature for Plant A will have little effect on the main ideas stated in the passage.
The passage states that spore counts are representative of the vegetation population at the time the pollen was deposited. If large differences in pollen production and dispersion are not accounted for, the percent concentration of pollen spores will not function as a representation of plant concentration in an area.
The method of selecting sample depth and the specific size/shape of pollen grains are not critical to the study's main idea.
Because the study gives no interpretation of the spore concentration data, changing the temperature for Plant A will have little effect on the main ideas stated in the passage.
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Adapted from "What is Ocean Acidification?" NOAA Pacific Marine Environmental Laboratory Carbon Program. NOAA. Web. 22 Apr. 2015. http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F.
The Chemistry
When carbon dioxide 
is absorbed by seawater, chemical reactions occur that reduce seawater pH, carbonate ion concentration, and saturation states of biologically important calcium carbonate minerals. These chemical reactions are termed "ocean acidification" or "OA" for short. Calcium carbonate minerals are the building blocks for the skeletons and shells of many marine organisms. In areas where most life now congregates in the ocean, the seawater is supersaturated with respect to calcium carbonate minerals. This means there are abundant building blocks for calcifying organisms to build their skeletons and shells. However, continued ocean acidification is causing many parts of the ocean to become undersaturated with these minerals, which is likely to affect the ability of some organisms to produce and maintain their shells.
Since the beginning of the Industrial Revolution, the pH of surface ocean waters has fallen by 0.1 pH units. Since the pH scale, like the Richter scale, is logarithmic, this change represents approximately a 30 percent increase in acidity. Future predictions indicate that the oceans will continue to absorb carbon dioxide and become even more acidic. Estimates of future carbon dioxide levels, based on business as usual emission scenarios, indicate that by the end of this century the surface waters of the ocean could be nearly 150 percent more acidic, resulting in a pH that the oceans haven’t experienced for more than 20 million years.
The Biological Impacts
Ocean acidification is expected to impact ocean species to varying degrees. Photosynthetic algae and seagrasses may benefit from higher 
conditions in the ocean, as they require 
to live just like plants on land. On the other hand, studies have shown that a more acidic environment has a dramatic effect on some calcifying species, including oysters, clams, sea urchins, shallow water corals, deep sea corals, and calcareous plankton. When shelled organisms are at risk, the entire food web may also be at risk. Today, more than a billion people worldwide rely on food from the ocean as their primary source of protein. Many jobs and economies in the U.S. and around the world depend on the fish and shellfish in our oceans.
Ocean Acidification: An Emerging Global Problem
Ocean acidification is an emerging global problem. Over the last decade, there has been much focus in the ocean science community on studying the potential impacts of ocean acidification. Since sustained efforts to monitor ocean acidification worldwide are only beginning, it is currently impossible to predict exactly how ocean acidification impacts will cascade throughout the marine food chain and affect the overall structure of marine ecosystems. With the pace of ocean acidification accelerating, scientists, resource managers, and policymakers recognize the urgent need to strengthen the science as a basis for sound decision-making and action.
According to the passage, where in the marine food web do shelled organisms sit?
Adapted from "What is Ocean Acidification?" NOAA Pacific Marine Environmental Laboratory Carbon Program. NOAA. Web. 22 Apr. 2015. http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F.
The Chemistry
When carbon dioxide
Since the beginning of the Industrial Revolution, the pH of surface ocean waters has fallen by 0.1 pH units. Since the pH scale, like the Richter scale, is logarithmic, this change represents approximately a 30 percent increase in acidity. Future predictions indicate that the oceans will continue to absorb carbon dioxide and become even more acidic. Estimates of future carbon dioxide levels, based on business as usual emission scenarios, indicate that by the end of this century the surface waters of the ocean could be nearly 150 percent more acidic, resulting in a pH that the oceans haven’t experienced for more than 20 million years.
The Biological Impacts
Ocean acidification is expected to impact ocean species to varying degrees. Photosynthetic algae and seagrasses may benefit from higher
Ocean Acidification: An Emerging Global Problem
Ocean acidification is an emerging global problem. Over the last decade, there has been much focus in the ocean science community on studying the potential impacts of ocean acidification. Since sustained efforts to monitor ocean acidification worldwide are only beginning, it is currently impossible to predict exactly how ocean acidification impacts will cascade throughout the marine food chain and affect the overall structure of marine ecosystems. With the pace of ocean acidification accelerating, scientists, resource managers, and policymakers recognize the urgent need to strengthen the science as a basis for sound decision-making and action.
According to the passage, where in the marine food web do shelled organisms sit?
One can infer that shelled organisms are not primary producers, yet they impact the food web in many significant ways, as is mentioned in the final paragraph of the passage. Thus they must sit towards the bottom, but not at the very bottom, as they are consumers, not producers.
One can infer that shelled organisms are not primary producers, yet they impact the food web in many significant ways, as is mentioned in the final paragraph of the passage. Thus they must sit towards the bottom, but not at the very bottom, as they are consumers, not producers.
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The origin of the universe has been a highly debated topic among physicists. In the middle of the twentieth century, there were two prevalent models regarding the origin of the universe. The first model, called the Big Bang Theory, suggests that the universe was spontaneously created approximately 14 billion years ago. The second model, called the Steady State Theory, suggests that the universe contains no beginning or end, is always expanding, and contains a constant density.
Initially, the Big Bang Theory was widely disregarded by physicists and astronomers. In fact, the name “Big Bang” was coined by Fred Hoyle, a supporter of the Steady State Theory, who used the term in a derogatory manner. The Big Bang Theory suggests that prior to the creation of matter, a physical object that occupies space and possesses mass, the universe was filled homogenously with high-energy density and very high temperature and pressure. The universe was rapidly expanding and cooling resulting in the creation of atoms. The initial atoms that were produced were much lighter than the atoms currently found on earth, the lightest of which are hydrogen, helium, and lithium. After this initial creation of the universe, it continued to expand. The Big Bang Theory is now the prevalent theory for the origin of the universe.
The Steady State Theory suggests that there is no start or end to the universe in time or space, yet the universe is always expanding. Furthermore, the Steady State Theory states that new stars and galaxies replace old stars and galaxies and the overall appearance of the universe does not change over time.
Two sources of evidence are used to support or refute the discussed hypotheses. The first piece of data is the presence of primordial gas clouds, pockets of the universe that contain gases lighter than those found in the current universe. The second piece of evidence is that other galaxies are “red shifted”. The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.
The Big Bang Theory states:
The origin of the universe has been a highly debated topic among physicists. In the middle of the twentieth century, there were two prevalent models regarding the origin of the universe. The first model, called the Big Bang Theory, suggests that the universe was spontaneously created approximately 14 billion years ago. The second model, called the Steady State Theory, suggests that the universe contains no beginning or end, is always expanding, and contains a constant density.
Initially, the Big Bang Theory was widely disregarded by physicists and astronomers. In fact, the name “Big Bang” was coined by Fred Hoyle, a supporter of the Steady State Theory, who used the term in a derogatory manner. The Big Bang Theory suggests that prior to the creation of matter, a physical object that occupies space and possesses mass, the universe was filled homogenously with high-energy density and very high temperature and pressure. The universe was rapidly expanding and cooling resulting in the creation of atoms. The initial atoms that were produced were much lighter than the atoms currently found on earth, the lightest of which are hydrogen, helium, and lithium. After this initial creation of the universe, it continued to expand. The Big Bang Theory is now the prevalent theory for the origin of the universe.
The Steady State Theory suggests that there is no start or end to the universe in time or space, yet the universe is always expanding. Furthermore, the Steady State Theory states that new stars and galaxies replace old stars and galaxies and the overall appearance of the universe does not change over time.
Two sources of evidence are used to support or refute the discussed hypotheses. The first piece of data is the presence of primordial gas clouds, pockets of the universe that contain gases lighter than those found in the current universe. The second piece of evidence is that other galaxies are “red shifted”. The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.
The Big Bang Theory states:
The Big Bang Theory states that the universe containing mass was created around 14 billion years ago when the universe was in a hot, dense state that was full of energy. The universe was cooling and expanding resulting in the creation of atoms (and mass). The first gases created contained elements that are smaller than those found on earth. The universe continues to expand.
The Big Bang Theory states that the universe containing mass was created around 14 billion years ago when the universe was in a hot, dense state that was full of energy. The universe was cooling and expanding resulting in the creation of atoms (and mass). The first gases created contained elements that are smaller than those found on earth. The universe continues to expand.
Compare your answer with the correct one above
The origin of the universe has been a highly debated topic among physicists. In the middle of the twentieth century, there were two prevalent models regarding the origin of the universe. The first model, called the Big Bang Theory, suggests that the universe was spontaneously created approximately 14 billion years ago. The second model, called the Steady State Theory, suggests that the universe contains no beginning or end, is always expanding, and contains a constant density.
Initially, the Big Bang Theory was widely disregarded by physicists and astronomers. In fact, the name “Big Bang” was coined by Fred Hoyle, a supporter of the Steady State Theory, who used the term in a derogatory manner. The Big Bang Theory suggests that prior to the creation of matter, a physical object that occupies space and possesses mass, the universe was filled homogenously with high-energy density and very high temperature and pressure. The universe was rapidly expanding and cooling resulting in the creation of atoms. The initial atoms that were produced were much lighter than the atoms currently found on earth, the lightest of which are hydrogen, helium, and lithium. After this initial creation of the universe, it continued to expand. The Big Bang Theory is now the prevalent theory for the origin of the universe.
The Steady State Theory suggests that there is no start or end to the universe in time or space, yet the universe is always expanding. Furthermore, the Steady State Theory states that new stars and galaxies replace old stars and galaxies and the overall appearance of the universe does not change over time.
Two sources of evidence are used to support or refute the discussed hypotheses. The first piece of data is the presence of primordial gas clouds, pockets of the universe that contain gases lighter than those found in the current universe. The second piece of evidence is that other galaxies are “red shifted”. The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.
Which word is defined as an object that contains mass and occupies space?
The origin of the universe has been a highly debated topic among physicists. In the middle of the twentieth century, there were two prevalent models regarding the origin of the universe. The first model, called the Big Bang Theory, suggests that the universe was spontaneously created approximately 14 billion years ago. The second model, called the Steady State Theory, suggests that the universe contains no beginning or end, is always expanding, and contains a constant density.
Initially, the Big Bang Theory was widely disregarded by physicists and astronomers. In fact, the name “Big Bang” was coined by Fred Hoyle, a supporter of the Steady State Theory, who used the term in a derogatory manner. The Big Bang Theory suggests that prior to the creation of matter, a physical object that occupies space and possesses mass, the universe was filled homogenously with high-energy density and very high temperature and pressure. The universe was rapidly expanding and cooling resulting in the creation of atoms. The initial atoms that were produced were much lighter than the atoms currently found on earth, the lightest of which are hydrogen, helium, and lithium. After this initial creation of the universe, it continued to expand. The Big Bang Theory is now the prevalent theory for the origin of the universe.
The Steady State Theory suggests that there is no start or end to the universe in time or space, yet the universe is always expanding. Furthermore, the Steady State Theory states that new stars and galaxies replace old stars and galaxies and the overall appearance of the universe does not change over time.
Two sources of evidence are used to support or refute the discussed hypotheses. The first piece of data is the presence of primordial gas clouds, pockets of the universe that contain gases lighter than those found in the current universe. The second piece of evidence is that other galaxies are “red shifted”. The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.
Which word is defined as an object that contains mass and occupies space?
The definition was provided in the text: The Big Bang Theory suggests that "prior to creation of matter, a physical object that occupies space and possesses mass . . ."
The definition was provided in the text: The Big Bang Theory suggests that "prior to creation of matter, a physical object that occupies space and possesses mass . . ."
Compare your answer with the correct one above
The origin of the universe has been a highly debated topic among physicists. In the middle of the twentieth century, there were two prevalent models regarding the origin of the universe. The first model, called the Big Bang Theory, suggests that the universe was spontaneously created approximately 14 billion years ago. The second model, called the Steady State Theory, suggests that the universe contains no beginning or end, is always expanding, and contains a constant density.
Initially, the Big Bang Theory was widely disregarded by physicists and astronomers. In fact, the name “Big Bang” was coined by Fred Hoyle, a supporter of the Steady State Theory, who used the term in a derogatory manner. The Big Bang Theory suggests that prior to the creation of matter, a physical object that occupies space and possesses mass, the universe was filled homogenously with high-energy density and very high temperature and pressure. The universe was rapidly expanding and cooling resulting in the creation of atoms. The initial atoms that were produced were much lighter than the atoms currently found on earth, the lightest of which are hydrogen, helium, and lithium. After this initial creation of the universe, it continued to expand. The Big Bang Theory is now the prevalent theory for the origin of the universe.
The Steady State Theory suggests that there is no start or end to the universe in time or space, yet the universe is always expanding. Furthermore, the Steady State Theory states that new stars and galaxies replace old stars and galaxies and the overall appearance of the universe does not change over time.
Two sources of evidence are used to support or refute the discussed hypotheses. The first piece of data is the presence of primordial gas clouds, pockets of the universe that contain gases lighter than those found in the current universe. The second piece of evidence is that other galaxies are “red shifted”. The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.
The Steady State Theory states:
The origin of the universe has been a highly debated topic among physicists. In the middle of the twentieth century, there were two prevalent models regarding the origin of the universe. The first model, called the Big Bang Theory, suggests that the universe was spontaneously created approximately 14 billion years ago. The second model, called the Steady State Theory, suggests that the universe contains no beginning or end, is always expanding, and contains a constant density.
Initially, the Big Bang Theory was widely disregarded by physicists and astronomers. In fact, the name “Big Bang” was coined by Fred Hoyle, a supporter of the Steady State Theory, who used the term in a derogatory manner. The Big Bang Theory suggests that prior to the creation of matter, a physical object that occupies space and possesses mass, the universe was filled homogenously with high-energy density and very high temperature and pressure. The universe was rapidly expanding and cooling resulting in the creation of atoms. The initial atoms that were produced were much lighter than the atoms currently found on earth, the lightest of which are hydrogen, helium, and lithium. After this initial creation of the universe, it continued to expand. The Big Bang Theory is now the prevalent theory for the origin of the universe.
The Steady State Theory suggests that there is no start or end to the universe in time or space, yet the universe is always expanding. Furthermore, the Steady State Theory states that new stars and galaxies replace old stars and galaxies and the overall appearance of the universe does not change over time.
Two sources of evidence are used to support or refute the discussed hypotheses. The first piece of data is the presence of primordial gas clouds, pockets of the universe that contain gases lighter than those found in the current universe. The second piece of evidence is that other galaxies are “red shifted”. The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.
The Steady State Theory states:
The Steady State theory claims the the universe has always existed in time and space and that its overall appearance does not change. This indicates that things may be created and destroyed, but new and old galaxies will appear identical.
The Steady State theory claims the the universe has always existed in time and space and that its overall appearance does not change. This indicates that things may be created and destroyed, but new and old galaxies will appear identical.
Compare your answer with the correct one above
The origin of the universe has been a highly debated topic among physicists. In the middle of the twentieth century, there were two prevalent models regarding the origin of the universe. The first model, called the Big Bang Theory, suggests that the universe was spontaneously created approximately 14 billion years ago. The second model, called the Steady State Theory, suggests that the universe contains no beginning or end, is always expanding, and contains a constant density.
Initially, the Big Bang Theory was widely disregarded by physicists and astronomers. In fact, the name “Big Bang” was coined by Fred Hoyle, a supporter of the Steady State Theory, who used the term in a derogatory manner. The Big Bang Theory suggests that prior to the creation of matter, a physical object that occupies space and possesses mass, the universe was filled homogenously with high-energy density and very high temperature and pressure. The universe was rapidly expanding and cooling resulting in the creation of atoms. The initial atoms that were produced were much lighter than the atoms currently found on earth, the lightest of which are hydrogen, helium, and lithium. After this initial creation of the universe, it continued to expand. The Big Bang Theory is now the prevalent theory for the origin of the universe.
The Steady State Theory suggests that there is no start or end to the universe in time or space, yet the universe is always expanding. Furthermore, the Steady State Theory states that new stars and galaxies replace old stars and galaxies and the overall appearance of the universe does not change over time.
Two sources of evidence are used to support or refute the discussed hypotheses. The first piece of data is the presence of primordial gas clouds, pockets of the universe that contain gases lighter than those found in the current universe. The second piece of evidence is that other galaxies are “red shifted”. The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.
A primordial gas has less mass than ________.
The origin of the universe has been a highly debated topic among physicists. In the middle of the twentieth century, there were two prevalent models regarding the origin of the universe. The first model, called the Big Bang Theory, suggests that the universe was spontaneously created approximately 14 billion years ago. The second model, called the Steady State Theory, suggests that the universe contains no beginning or end, is always expanding, and contains a constant density.
Initially, the Big Bang Theory was widely disregarded by physicists and astronomers. In fact, the name “Big Bang” was coined by Fred Hoyle, a supporter of the Steady State Theory, who used the term in a derogatory manner. The Big Bang Theory suggests that prior to the creation of matter, a physical object that occupies space and possesses mass, the universe was filled homogenously with high-energy density and very high temperature and pressure. The universe was rapidly expanding and cooling resulting in the creation of atoms. The initial atoms that were produced were much lighter than the atoms currently found on earth, the lightest of which are hydrogen, helium, and lithium. After this initial creation of the universe, it continued to expand. The Big Bang Theory is now the prevalent theory for the origin of the universe.
The Steady State Theory suggests that there is no start or end to the universe in time or space, yet the universe is always expanding. Furthermore, the Steady State Theory states that new stars and galaxies replace old stars and galaxies and the overall appearance of the universe does not change over time.
Two sources of evidence are used to support or refute the discussed hypotheses. The first piece of data is the presence of primordial gas clouds, pockets of the universe that contain gases lighter than those found in the current universe. The second piece of evidence is that other galaxies are “red shifted”. The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.
A primordial gas has less mass than ________.
The primoridal gases at the creation of the universe contained less mass than the elements on earth today. Hydrogen is the smallest element, therefore, primordial gases must comprise less mass than hydrogen. Atoms can vary in size and mass based on the type. Energy and light do not contain mass.
The primoridal gases at the creation of the universe contained less mass than the elements on earth today. Hydrogen is the smallest element, therefore, primordial gases must comprise less mass than hydrogen. Atoms can vary in size and mass based on the type. Energy and light do not contain mass.
Compare your answer with the correct one above
The origin of the universe has been a highly debated topic among physicists. In the middle of the twentieth century, there were two prevalent models regarding the origin of the universe. The first model, called the Big Bang Theory, suggests that the universe was spontaneously created approximately 14 billion years ago. The second model, called the Steady State Theory, suggests that the universe contains no beginning or end, is always expanding, and contains a constant density.
Initially, the Big Bang Theory was widely disregarded by physicists and astronomers. In fact, the name “Big Bang” was coined by Fred Hoyle, a supporter of the Steady State Theory, who used the term in a derogatory manner. The Big Bang Theory suggests that prior to the creation of matter, a physical object that occupies space and possesses mass, the universe was filled homogenously with high-energy density and very high temperature and pressure. The universe was rapidly expanding and cooling resulting in the creation of atoms. The initial atoms that were produced were much lighter than the atoms currently found on earth, the lightest of which are hydrogen, helium, and lithium. After this initial creation of the universe, it continued to expand. The Big Bang Theory is now the prevalent theory for the origin of the universe.
The Steady State Theory suggests that there is no start or end to the universe in time or space, yet the universe is always expanding. Furthermore, the Steady State Theory states that new stars and galaxies replace old stars and galaxies and the overall appearance of the universe does not change over time.
Two sources of evidence are used to support or refute the discussed hypotheses. The first piece of data is the presence of primordial gas clouds, pockets of the universe that contain gases lighter than those found in the current universe. The second piece of evidence is that other galaxies are “red shifted”. The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.
A red-shift can be used to estimate_________.
The origin of the universe has been a highly debated topic among physicists. In the middle of the twentieth century, there were two prevalent models regarding the origin of the universe. The first model, called the Big Bang Theory, suggests that the universe was spontaneously created approximately 14 billion years ago. The second model, called the Steady State Theory, suggests that the universe contains no beginning or end, is always expanding, and contains a constant density.
Initially, the Big Bang Theory was widely disregarded by physicists and astronomers. In fact, the name “Big Bang” was coined by Fred Hoyle, a supporter of the Steady State Theory, who used the term in a derogatory manner. The Big Bang Theory suggests that prior to the creation of matter, a physical object that occupies space and possesses mass, the universe was filled homogenously with high-energy density and very high temperature and pressure. The universe was rapidly expanding and cooling resulting in the creation of atoms. The initial atoms that were produced were much lighter than the atoms currently found on earth, the lightest of which are hydrogen, helium, and lithium. After this initial creation of the universe, it continued to expand. The Big Bang Theory is now the prevalent theory for the origin of the universe.
The Steady State Theory suggests that there is no start or end to the universe in time or space, yet the universe is always expanding. Furthermore, the Steady State Theory states that new stars and galaxies replace old stars and galaxies and the overall appearance of the universe does not change over time.
Two sources of evidence are used to support or refute the discussed hypotheses. The first piece of data is the presence of primordial gas clouds, pockets of the universe that contain gases lighter than those found in the current universe. The second piece of evidence is that other galaxies are “red shifted”. The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.
A red-shift can be used to estimate_________.
From the text: The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.
Therefore, an object that has a red-shift is moving farther away from the observer. This phenomenon can be used to determine if galaxies are moving farther away.
From the text: The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.
Therefore, an object that has a red-shift is moving farther away from the observer. This phenomenon can be used to determine if galaxies are moving farther away.
Compare your answer with the correct one above
Global warming is defined as the slow increase in the temperature of the earth’s atmosphere and is caused by pollutants and carbon dioxide (CO2). While the gradual increase in temperature cannot be refuted, scientists argue over the cause.
Scientist 1:
Global warming is caused by increases in atmospheric CO2, which is directly created by humans and their consumption of fossil fuels. The natural CO2 released from carbon sinks has a different isotopic ratio from the CO2 released from fossil fuels. Current measurements of the radioactive isotopes of CO2 show that it is from human activity, not from nature. The Earth’s carbon sinks cannot absorb these large amounts of unnatural CO2 emissions. About fifty percent of the CO2 produced by mankind remains in the atmosphere, unable to be absorbed.
Scientist 2:
The rise in atmospheric CO2 levels are a result of global warming, not the cause of it. When the temperature increases, the CO2 in carbon sinks is released. While humans do cause release of CO2, the carbon sinks absorb it. The activity of the carbon sinks increases to allow for higher levels of CO2 absorption. Proponents for human causation of global warming point to the warming and cooling of the stratosphere, however, these temperature fluctuations are caused by changes in the sun’s heat. These proponents also look at the acidity of the ocean as evidence of human causation, however, the rise in ocean acidity is within the normal range of fluctuations over the past ten thousand years.
Scientist 1 uses which of the following as evidence towards human causation of global warming?
Global warming is defined as the slow increase in the temperature of the earth’s atmosphere and is caused by pollutants and carbon dioxide (CO2). While the gradual increase in temperature cannot be refuted, scientists argue over the cause.
Scientist 1:
Global warming is caused by increases in atmospheric CO2, which is directly created by humans and their consumption of fossil fuels. The natural CO2 released from carbon sinks has a different isotopic ratio from the CO2 released from fossil fuels. Current measurements of the radioactive isotopes of CO2 show that it is from human activity, not from nature. The Earth’s carbon sinks cannot absorb these large amounts of unnatural CO2 emissions. About fifty percent of the CO2 produced by mankind remains in the atmosphere, unable to be absorbed.
Scientist 2:
The rise in atmospheric CO2 levels are a result of global warming, not the cause of it. When the temperature increases, the CO2 in carbon sinks is released. While humans do cause release of CO2, the carbon sinks absorb it. The activity of the carbon sinks increases to allow for higher levels of CO2 absorption. Proponents for human causation of global warming point to the warming and cooling of the stratosphere, however, these temperature fluctuations are caused by changes in the sun’s heat. These proponents also look at the acidity of the ocean as evidence of human causation, however, the rise in ocean acidity is within the normal range of fluctuations over the past ten thousand years.
Scientist 1 uses which of the following as evidence towards human causation of global warming?
Scientist 1 suggests that the natural CO2 released from carbon sinks has a different isotopic ratio from the CO2 released from fossil fuels. Current measurements of the radioactive isotopes of CO2 show that it is from human activity, not from nature.
Scientist 1 suggests that the natural CO2 released from carbon sinks has a different isotopic ratio from the CO2 released from fossil fuels. Current measurements of the radioactive isotopes of CO2 show that it is from human activity, not from nature.
Compare your answer with the correct one above
Global warming is defined as the slow increase in the temperature of the earth’s atmosphere and is caused by pollutants and carbon dioxide (CO2). While the gradual increase in temperature cannot be refuted, scientists argue over the cause.
Scientist 1:
Global warming is caused by increases in atmospheric CO2, which is directly created by humans and their consumption of fossil fuels. The natural CO2 released from carbon sinks has a different isotopic ratio from the CO2 released from fossil fuels. Current measurements of the radioactive isotopes of CO2 show that it is from human activity, not from nature. The Earth’s carbon sinks cannot absorb these large amounts of unnatural CO2 emissions. About fifty percent of the CO2 produced by mankind remains in the atmosphere, unable to be absorbed.
Scientist 2:
The rise in atmospheric CO2 levels are a result of global warming, not the cause of it. When the temperature increases, the CO2 in carbon sinks is released. While humans do cause release of CO2, the carbon sinks absorb it. The activity of the carbon sinks increases to allow for higher levels of CO2 absorption. Proponents for human causation of global warming point to the warming and cooling of the stratosphere, however, these temperature fluctuations are caused by changes in the sun’s heat. These proponents also look at the acidity of the ocean as evidence of human causation, however, the rise in ocean acidity is within the normal range of fluctuations over the past ten thousand years.
What new evidence would support the argument made by Scientist 2?
Global warming is defined as the slow increase in the temperature of the earth’s atmosphere and is caused by pollutants and carbon dioxide (CO2). While the gradual increase in temperature cannot be refuted, scientists argue over the cause.
Scientist 1:
Global warming is caused by increases in atmospheric CO2, which is directly created by humans and their consumption of fossil fuels. The natural CO2 released from carbon sinks has a different isotopic ratio from the CO2 released from fossil fuels. Current measurements of the radioactive isotopes of CO2 show that it is from human activity, not from nature. The Earth’s carbon sinks cannot absorb these large amounts of unnatural CO2 emissions. About fifty percent of the CO2 produced by mankind remains in the atmosphere, unable to be absorbed.
Scientist 2:
The rise in atmospheric CO2 levels are a result of global warming, not the cause of it. When the temperature increases, the CO2 in carbon sinks is released. While humans do cause release of CO2, the carbon sinks absorb it. The activity of the carbon sinks increases to allow for higher levels of CO2 absorption. Proponents for human causation of global warming point to the warming and cooling of the stratosphere, however, these temperature fluctuations are caused by changes in the sun’s heat. These proponents also look at the acidity of the ocean as evidence of human causation, however, the rise in ocean acidity is within the normal range of fluctuations over the past ten thousand years.
What new evidence would support the argument made by Scientist 2?
Evidence showing that temperature increase predated the release of CO2 from carbon sinks would support the theory of Scientist 2. Scientist 2 argues that the rising temperature led to an increase in atmospheric CO2, rather than CO2 leading to an increase in temperature. An increase in temperature before an increase in CO2 would be consistent with this reasoning.
Evidence showing that temperature increase predated the release of CO2 from carbon sinks would support the theory of Scientist 2. Scientist 2 argues that the rising temperature led to an increase in atmospheric CO2, rather than CO2 leading to an increase in temperature. An increase in temperature before an increase in CO2 would be consistent with this reasoning.
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A scientist observes the motion of stars, planets, and other objects in deep space through a high-powered telescope. She observes that these objects all appear to be moving away from the Earth and graphs her results comparing their velocities, in kilometers per second, and their proper distance, in megaparsecs.
Based on this graph, which of the following conclusions is valid?
A scientist observes the motion of stars, planets, and other objects in deep space through a high-powered telescope. She observes that these objects all appear to be moving away from the Earth and graphs her results comparing their velocities, in kilometers per second, and their proper distance, in megaparsecs.
Based on this graph, which of the following conclusions is valid?
Based upon the graph, the farther away the object is, the higher it's velocity away from the earth. Since the graph is linear, then the two are proportional.
Based upon the graph, the farther away the object is, the higher it's velocity away from the earth. Since the graph is linear, then the two are proportional.
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A scientist observes the motion of stars, planets, and other objects in deep space through a high-powered telescope. She observes that these objects all appear to be moving away from the Earth and graphs her results comparing their velocities, in kilometers per second, and their proper distance, in megaparsecs.
Which one of the following statements, if true, best supports the findings of this experiment?
A scientist observes the motion of stars, planets, and other objects in deep space through a high-powered telescope. She observes that these objects all appear to be moving away from the Earth and graphs her results comparing their velocities, in kilometers per second, and their proper distance, in megaparsecs.
Which one of the following statements, if true, best supports the findings of this experiment?
The best solution is that the universe is ever-expanding. While our given graph does not expand infinitely, the line will extend infinitely -- we can extrapolate the velocity of an object of any distance away from the Earth. We can do so up to infinity, thus leading to the conclusion that the universe is ever-expanding.
The best solution is that the universe is ever-expanding. While our given graph does not expand infinitely, the line will extend infinitely -- we can extrapolate the velocity of an object of any distance away from the Earth. We can do so up to infinity, thus leading to the conclusion that the universe is ever-expanding.
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A scientist observes the motion of stars, planets, and other objects in deep space through a high-powered telescope. She observes that these objects all appear to be moving away from the Earth and graphs her results comparing their velocities, in kilometers per second, and their proper distance, in megaparsecs.
A new star is observed. Which of the following pieces of information is necessary to find out how far away it is?
A scientist observes the motion of stars, planets, and other objects in deep space through a high-powered telescope. She observes that these objects all appear to be moving away from the Earth and graphs her results comparing their velocities, in kilometers per second, and their proper distance, in megaparsecs.
A new star is observed. Which of the following pieces of information is necessary to find out how far away it is?
The only thing we need in order to use this graph is the velocity of the star. If we can find the velocity, we can find the distance.
The only thing we need in order to use this graph is the velocity of the star. If we can find the velocity, we can find the distance.
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Scientists have long debated the origin of organic molecules on Earth. Organic molecules are those based on the atom carbon, which can form four distinct bonds in contrast to the fewer number allowed in most other non-metals. As a result of this property, carbon can give rise to the enormously complex molecular shapes necessary for life to arise.
Some scientists argue that organic matter was dissolved in water ice on comets, and brought to Earth early in its history. These comets crashed into the early Earth, and deposited carbon-based molecules in copious quantities to the Earth’s surface as their water melted.
In 2014, the first space probe landed on the comet 67P/Churyumov-Gerasimenko. Suppose that scientists find the following information from 5 distinct samples after landing on the comet. Each sample was taken at a single geographical location, but 5 meters deeper than the last. Sample 1 was taken at a depth of 1 meter below the surface.
Sample # Water Ice? Concentration of Organics 1 No N/A 2 Yes 1 mg/L 3 No N/A 4 Yes 4 mg/L 5 Yes 10 mg/L
These samples were compared to 5 similar samples from the surface of Mars. Scientists posited that this comparison would be meaningful because we know that life does not exist on Mars the same way that it does on Earth. Thus, they are comparing a known non-biological celestial body, Mars, with another celestial body, the comet, which may be seeding life on suitable plants.
Sample # Water Ice? Concentration of Organics 1 No N/A 2 No N/A 3 No N/A 4 No N/A 5 Yes 1 mg/L
The data presented in the passage most closely support the idea that:
Scientists have long debated the origin of organic molecules on Earth. Organic molecules are those based on the atom carbon, which can form four distinct bonds in contrast to the fewer number allowed in most other non-metals. As a result of this property, carbon can give rise to the enormously complex molecular shapes necessary for life to arise.
Some scientists argue that organic matter was dissolved in water ice on comets, and brought to Earth early in its history. These comets crashed into the early Earth, and deposited carbon-based molecules in copious quantities to the Earth’s surface as their water melted.
In 2014, the first space probe landed on the comet 67P/Churyumov-Gerasimenko. Suppose that scientists find the following information from 5 distinct samples after landing on the comet. Each sample was taken at a single geographical location, but 5 meters deeper than the last. Sample 1 was taken at a depth of 1 meter below the surface.
| Sample # | Water Ice? | Concentration of Organics |
|---|---|---|
| 1 | No | N/A |
| 2 | Yes | 1 mg/L |
| 3 | No | N/A |
| 4 | Yes | 4 mg/L |
| 5 | Yes | 10 mg/L |
These samples were compared to 5 similar samples from the surface of Mars. Scientists posited that this comparison would be meaningful because we know that life does not exist on Mars the same way that it does on Earth. Thus, they are comparing a known non-biological celestial body, Mars, with another celestial body, the comet, which may be seeding life on suitable plants.
| Sample # | Water Ice? | Concentration of Organics |
|---|---|---|
| 1 | No | N/A |
| 2 | No | N/A |
| 3 | No | N/A |
| 4 | No | N/A |
| 5 | Yes | 1 mg/L |
The data presented in the passage most closely support the idea that:
The observation of greater concentrations of organics on the comet as compared to Mars suggests that comets at least have the potential to have seeded organic molecules on the eartly Earth.
The observation of greater concentrations of organics on the comet as compared to Mars suggests that comets at least have the potential to have seeded organic molecules on the eartly Earth.
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Scientists have long debated the origin of organic molecules on Earth. Organic molecules are those based on the atom carbon, which can form four distinct bonds in contrast to the fewer number allowed in most other non-metals. As a result of this property, carbon can give rise to the enormously complex molecular shapes necessary for life to arise.
Some scientists argue that organic matter was dissolved in water ice on comets, and brought to Earth early in its history. These comets crashed into the early Earth, and deposited carbon-based molecules in copious quantities to the Earth’s surface as their water melted.
In 2014, the first space probe landed on the comet 67P/Churyumov-Gerasimenko. Suppose that scientists find the following information from 5 distinct samples after landing on the comet. Each sample was taken at a single geographical location, but 5 meters deeper than the last. Sample 1 was taken at a depth of 1 meter below the surface.
Sample # Water Ice? Concentration of Organics 1 No N/A 2 Yes 1 mg/L 3 No N/A 4 Yes 4 mg/L 5 Yes 10 mg/L
These samples were compared to 5 similar samples from the surface of Mars. Scientists posited that this comparison would be meaningful because we know that life does not exist on Mars the same way that it does on Earth. Thus, they are comparing a known non-biological celestial body, Mars, with another celestial body, the comet, which may be seeding life on suitable plants.
Sample # Water Ice? Concentration of Organics 1 No N/A 2 No N/A 3 No N/A 4 No N/A 5 Yes 1 mg/L
Which of the following facts would be most supportive of the suggestion that comets seeded organic molecules on Earth before life first developed?
Scientists have long debated the origin of organic molecules on Earth. Organic molecules are those based on the atom carbon, which can form four distinct bonds in contrast to the fewer number allowed in most other non-metals. As a result of this property, carbon can give rise to the enormously complex molecular shapes necessary for life to arise.
Some scientists argue that organic matter was dissolved in water ice on comets, and brought to Earth early in its history. These comets crashed into the early Earth, and deposited carbon-based molecules in copious quantities to the Earth’s surface as their water melted.
In 2014, the first space probe landed on the comet 67P/Churyumov-Gerasimenko. Suppose that scientists find the following information from 5 distinct samples after landing on the comet. Each sample was taken at a single geographical location, but 5 meters deeper than the last. Sample 1 was taken at a depth of 1 meter below the surface.
| Sample # | Water Ice? | Concentration of Organics |
|---|---|---|
| 1 | No | N/A |
| 2 | Yes | 1 mg/L |
| 3 | No | N/A |
| 4 | Yes | 4 mg/L |
| 5 | Yes | 10 mg/L |
These samples were compared to 5 similar samples from the surface of Mars. Scientists posited that this comparison would be meaningful because we know that life does not exist on Mars the same way that it does on Earth. Thus, they are comparing a known non-biological celestial body, Mars, with another celestial body, the comet, which may be seeding life on suitable plants.
| Sample # | Water Ice? | Concentration of Organics |
|---|---|---|
| 1 | No | N/A |
| 2 | No | N/A |
| 3 | No | N/A |
| 4 | No | N/A |
| 5 | Yes | 1 mg/L |
Which of the following facts would be most supportive of the suggestion that comets seeded organic molecules on Earth before life first developed?
The concept of seeding organic molecules to help jump start the evolution of life on Earth demands that early comet strikes took place. Thus, the early, frequent collisions of organics-rich comets with the Earth would be most consistent with this hypothesis.
The concept of seeding organic molecules to help jump start the evolution of life on Earth demands that early comet strikes took place. Thus, the early, frequent collisions of organics-rich comets with the Earth would be most consistent with this hypothesis.
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Scientists have long debated the origin of organic molecules on Earth. Organic molecules are those based on the atom carbon, which can form four distinct bonds in contrast to the fewer number allowed in most other non-metals. As a result of this property, carbon can give rise to the enormously complex molecular shapes necessary for life to arise.
Some scientists argue that organic matter was dissolved in water ice on comets, and brought to Earth early in its history. These comets crashed into the early Earth, and deposited carbon-based molecules in copious quantities to the Earth’s surface as their water melted.
In 2014, the first space probe landed on the comet 67P/Churyumov-Gerasimenko. Suppose that scientists find the following information from 5 distinct samples after landing on the comet. Each sample was taken at a single geographical location, but 5 meters deeper than the last. Sample 1 was taken at a depth of 1 meter below the surface.
Sample # Water Ice? Concentration of Organics 1 No N/A 2 Yes 1 mg/L 3 No N/A 4 Yes 4 mg/L 5 Yes 10 mg/L
These samples were compared to 5 similar samples from the surface of Mars. Scientists posited that this comparison would be meaningful because we know that life does not exist on Mars the same way that it does on Earth. Thus, they are comparing a known non-biological celestial body, Mars, with another celestial body, the comet, which may be seeding life on suitable plants.
Sample # Water Ice? Concentration of Organics 1 No N/A 2 No N/A 3 No N/A 4 No N/A 5 Yes 1 mg/L
Suppose a scientist concludes, based on these data, that organics are in fact dissolved in the water ice of the comet. Which of the following would most directly undermine this finding?
Scientists have long debated the origin of organic molecules on Earth. Organic molecules are those based on the atom carbon, which can form four distinct bonds in contrast to the fewer number allowed in most other non-metals. As a result of this property, carbon can give rise to the enormously complex molecular shapes necessary for life to arise.
Some scientists argue that organic matter was dissolved in water ice on comets, and brought to Earth early in its history. These comets crashed into the early Earth, and deposited carbon-based molecules in copious quantities to the Earth’s surface as their water melted.
In 2014, the first space probe landed on the comet 67P/Churyumov-Gerasimenko. Suppose that scientists find the following information from 5 distinct samples after landing on the comet. Each sample was taken at a single geographical location, but 5 meters deeper than the last. Sample 1 was taken at a depth of 1 meter below the surface.
| Sample # | Water Ice? | Concentration of Organics |
|---|---|---|
| 1 | No | N/A |
| 2 | Yes | 1 mg/L |
| 3 | No | N/A |
| 4 | Yes | 4 mg/L |
| 5 | Yes | 10 mg/L |
These samples were compared to 5 similar samples from the surface of Mars. Scientists posited that this comparison would be meaningful because we know that life does not exist on Mars the same way that it does on Earth. Thus, they are comparing a known non-biological celestial body, Mars, with another celestial body, the comet, which may be seeding life on suitable plants.
| Sample # | Water Ice? | Concentration of Organics |
|---|---|---|
| 1 | No | N/A |
| 2 | No | N/A |
| 3 | No | N/A |
| 4 | No | N/A |
| 5 | Yes | 1 mg/L |
Suppose a scientist concludes, based on these data, that organics are in fact dissolved in the water ice of the comet. Which of the following would most directly undermine this finding?
The biological feasability of the organics does not have direct relevance on the reliability of these data suggesting that they are found in the comet. Alternatively, the comet is known to have water ice, and the suggestion from the data is that this water ice is the solvent for these organics. If the found organics are not actually soluble in water ice, it would suggest that they are contaminants and not actually found in the comet. This would undermine the scientist's conclusion.
The biological feasability of the organics does not have direct relevance on the reliability of these data suggesting that they are found in the comet. Alternatively, the comet is known to have water ice, and the suggestion from the data is that this water ice is the solvent for these organics. If the found organics are not actually soluble in water ice, it would suggest that they are contaminants and not actually found in the comet. This would undermine the scientist's conclusion.
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Scientists studying historical trends in climate change have a number of tools at their disposal. One method of analyzing paleoclimate data involves the use of fossilized pollen spores embedded in sediment. Pollen spores are specific to the plant that produced them. Because the spores are resilient and are widely-distributed by wind, they provide a snapshot of the vegetation that was widespread at a particular point in time. By identifying the age of a sample and the composition of the various spores, scientists can identify the prominent vegetation and use this information to gain insight into the climate at the time the spores were deposited.
Scientists took sediment samples from various depths of a lakebed. They found that five types of pollen spores make up the majority of spore deposits in each sample. In Table 1, plants are listed along with the respective temperature ranges and levels of precipitation for the areas in which they are commonly found. Table 2 shows the composition of the assortment of spores in each of the four samples taken by the scientists.
Which of the following explains why pollen spores are useful in the study of historical trends in climate change?
Scientists studying historical trends in climate change have a number of tools at their disposal. One method of analyzing paleoclimate data involves the use of fossilized pollen spores embedded in sediment. Pollen spores are specific to the plant that produced them. Because the spores are resilient and are widely-distributed by wind, they provide a snapshot of the vegetation that was widespread at a particular point in time. By identifying the age of a sample and the composition of the various spores, scientists can identify the prominent vegetation and use this information to gain insight into the climate at the time the spores were deposited.
Scientists took sediment samples from various depths of a lakebed. They found that five types of pollen spores make up the majority of spore deposits in each sample. In Table 1, plants are listed along with the respective temperature ranges and levels of precipitation for the areas in which they are commonly found. Table 2 shows the composition of the assortment of spores in each of the four samples taken by the scientists.
Which of the following explains why pollen spores are useful in the study of historical trends in climate change?
From the passage: "Because the spores are resilient and are widely-distributed by wind, they provide a snapshot of the vegetation that was widespread at a particular point in time."
Therefore, it is important that pollen spores are resilient in order to study their concentration long after they were deposited.
From the passage: "Because the spores are resilient and are widely-distributed by wind, they provide a snapshot of the vegetation that was widespread at a particular point in time."
Therefore, it is important that pollen spores are resilient in order to study their concentration long after they were deposited.
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Scientists studying historical trends in climate change have a number of tools at their disposal. One method of analyzing paleoclimate data involves the use of fossilized pollen spores embedded in sediment. Pollen spores are specific to the plant that produced them. Because the spores are resilient and are widely-distributed by wind, they provide a snapshot of the vegetation that was widespread at a particular point in time. By identifying the age of a sample and the composition of the various spores, scientists can identify the prominent vegetation and use this information to gain insight into the climate at the time the spores were deposited.
Scientists took sediment samples from various depths of a lakebed. They found that five types of pollen spores make up the majority of spore deposits in each sample. In Table 1, plants are listed along with the respective temperature ranges and levels of precipitation for the areas in which they are commonly found. Table 2 shows the composition of the assortment of spores in each of the four samples taken by the scientists.
Based on the evidence, which of the following conclusions is valid?
Scientists studying historical trends in climate change have a number of tools at their disposal. One method of analyzing paleoclimate data involves the use of fossilized pollen spores embedded in sediment. Pollen spores are specific to the plant that produced them. Because the spores are resilient and are widely-distributed by wind, they provide a snapshot of the vegetation that was widespread at a particular point in time. By identifying the age of a sample and the composition of the various spores, scientists can identify the prominent vegetation and use this information to gain insight into the climate at the time the spores were deposited.
Scientists took sediment samples from various depths of a lakebed. They found that five types of pollen spores make up the majority of spore deposits in each sample. In Table 1, plants are listed along with the respective temperature ranges and levels of precipitation for the areas in which they are commonly found. Table 2 shows the composition of the assortment of spores in each of the four samples taken by the scientists.
Based on the evidence, which of the following conclusions is valid?
Because the total number of spores in each sample was not given, we cannot determine whether plant populations increased or decreased. Likewise, because sample depth was not given, there is no indication of whether temperature rose or fell with increasing sample depth. As stated in the passage, spore concentration indicates which plants were most common at a given time. This is directly tied to the climate of a particular era.
Because the total number of spores in each sample was not given, we cannot determine whether plant populations increased or decreased. Likewise, because sample depth was not given, there is no indication of whether temperature rose or fell with increasing sample depth. As stated in the passage, spore concentration indicates which plants were most common at a given time. This is directly tied to the climate of a particular era.
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Study 1
A student wishes to study the effects of various household detergents on the mortality of a certain type of bacteria over an extended period of time. She introduces that type of bacteria to four separate agar plates (labeled Plate 1, Plate 2, Plate 3, and Plate 4), and then allows the bacteria to grow for three days. After this period, she treats Plate 1 with water, Plate 2 with Detergent X, Plate 3 with Detergent Y, and Plate 4 with Detergent Z. She then counts the number of bacterial colonies on each plate every eight hours for the next twenty-four hours.
Table 1
Study 2
The student now wishes to compare the effects of Detergent X and Detergent Y on the same type of bacteria as she used in Study 1. The student introduces that type of bacteria to three separate plates (labeled Plate I, Plate II, and Plate III), and then allows the bacteria to grow for 3 days. After this period, she treats Plate I with water, Plate II with Detergent X, and Plate III with Detergent Y. She then counts the number of bacterial colonies on each plate every eight hours for the next forty-eight hours.
Which of the following best describes the relationship between time and the number of bacterial colonies on Plate 2 in Study 1?
Study 1
A student wishes to study the effects of various household detergents on the mortality of a certain type of bacteria over an extended period of time. She introduces that type of bacteria to four separate agar plates (labeled Plate 1, Plate 2, Plate 3, and Plate 4), and then allows the bacteria to grow for three days. After this period, she treats Plate 1 with water, Plate 2 with Detergent X, Plate 3 with Detergent Y, and Plate 4 with Detergent Z. She then counts the number of bacterial colonies on each plate every eight hours for the next twenty-four hours.
Table 1
Study 2
The student now wishes to compare the effects of Detergent X and Detergent Y on the same type of bacteria as she used in Study 1. The student introduces that type of bacteria to three separate plates (labeled Plate I, Plate II, and Plate III), and then allows the bacteria to grow for 3 days. After this period, she treats Plate I with water, Plate II with Detergent X, and Plate III with Detergent Y. She then counts the number of bacterial colonies on each plate every eight hours for the next forty-eight hours.
Which of the following best describes the relationship between time and the number of bacterial colonies on Plate 2 in Study 1?
From inspection of the table, we see that every eight hours, the number of bacterial colonies on Plate 2 is halved. Thus, the number of colonies on this plate is decreasing exponentially as time progresses.
From inspection of the table, we see that every eight hours, the number of bacterial colonies on Plate 2 is halved. Thus, the number of colonies on this plate is decreasing exponentially as time progresses.
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Study 1
A student wishes to study the effects of various household detergents on the mortality of a certain type of bacteria over an extended period of time. She introduces that type of bacteria to four separate agar plates (labeled Plate 1, Plate 2, Plate 3, and Plate 4), and then allows the bacteria to grow for three days. After this period, she treats Plate 1 with water, Plate 2 with Detergent X, Plate 3 with Detergent Y, and Plate 4 with Detergent Z. She then counts the number of bacterial colonies on each plate every eight hours for the next twenty-four hours.
Table 1
Study 2
The student now wishes to compare the effects of Detergent X and Detergent Y on the same type of bacteria as she used in Study 1. The student introduces that type of bacteria to three separate plates (labeled Plate I, Plate II, and Plate III), and then allows the bacteria to grow for 3 days. After this period, she treats Plate I with water, Plate II with Detergent X, and Plate III with Detergent Y. She then counts the number of bacterial colonies on each plate every eight hours for the next forty-eight hours.
Which of the following is a reasonable conclusion to draw from the graph associated with Study 2?
Study 1
A student wishes to study the effects of various household detergents on the mortality of a certain type of bacteria over an extended period of time. She introduces that type of bacteria to four separate agar plates (labeled Plate 1, Plate 2, Plate 3, and Plate 4), and then allows the bacteria to grow for three days. After this period, she treats Plate 1 with water, Plate 2 with Detergent X, Plate 3 with Detergent Y, and Plate 4 with Detergent Z. She then counts the number of bacterial colonies on each plate every eight hours for the next twenty-four hours.
Table 1
Study 2
The student now wishes to compare the effects of Detergent X and Detergent Y on the same type of bacteria as she used in Study 1. The student introduces that type of bacteria to three separate plates (labeled Plate I, Plate II, and Plate III), and then allows the bacteria to grow for 3 days. After this period, she treats Plate I with water, Plate II with Detergent X, and Plate III with Detergent Y. She then counts the number of bacterial colonies on each plate every eight hours for the next forty-eight hours.
Which of the following is a reasonable conclusion to draw from the graph associated with Study 2?
The curve corresponding to Plate III (which contains Detergent Y) decreases most quickly at first, but it plateaus at about twenty-four hours, whereas the curve corresponding to Plate II does not plateau until several hours later.
The curve corresponding to Plate III (which contains Detergent Y) decreases most quickly at first, but it plateaus at about twenty-four hours, whereas the curve corresponding to Plate II does not plateau until several hours later.
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Adapted from "What is Ocean Acidification?" NOAA Pacific Marine Environmental Laboratory Carbon Program. NOAA. Web. 22 Apr. 2015. http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F.
The Chemistry
When carbon dioxide is absorbed by seawater, chemical reactions occur that reduce seawater pH, carbonate ion concentration, and saturation states of biologically important calcium carbonate minerals. These chemical reactions are termed "ocean acidification" or "OA" for short. Calcium carbonate minerals are the building blocks for the skeletons and shells of many marine organisms. In areas where most life now congregates in the ocean, the seawater is supersaturated with respect to calcium carbonate minerals. This means there are abundant building blocks for calcifying organisms to build their skeletons and shells. However, continued ocean acidification is causing many parts of the ocean to become undersaturated with these minerals, which is likely to affect the ability of some organisms to produce and maintain their shells.
Since the beginning of the Industrial Revolution, the pH of surface ocean waters has fallen by 0.1 pH units. Since the pH scale, like the Richter scale, is logarithmic, this change represents approximately a 30 percent increase in acidity. Future predictions indicate that the oceans will continue to absorb carbon dioxide and become even more acidic. Estimates of future carbon dioxide levels, based on business as usual emission scenarios, indicate that by the end of this century the surface waters of the ocean could be nearly 150 percent more acidic, resulting in a pH that the oceans haven’t experienced for more than 20 million years.
The Biological Impacts
Ocean acidification is expected to impact ocean species to varying degrees. Photosynthetic algae and seagrasses may benefit from higher conditions in the ocean, as they require to live just like plants on land. On the other hand, studies have shown that a more acidic environment has a dramatic effect on some calcifying species, including oysters, clams, sea urchins, shallow water corals, deep sea corals, and calcareous plankton. When shelled organisms are at risk, the entire food web may also be at risk. Today, more than a billion people worldwide rely on food from the ocean as their primary source of protein. Many jobs and economies in the U.S. and around the world depend on the fish and shellfish in our oceans.
Ocean Acidification: An Emerging Global Problem
Ocean acidification is an emerging global problem. Over the last decade, there has been much focus in the ocean science community on studying the potential impacts of ocean acidification. Since sustained efforts to monitor ocean acidification worldwide are only beginning, it is currently impossible to predict exactly how ocean acidification impacts will cascade throughout the marine food chain and affect the overall structure of marine ecosystems. With the pace of ocean acidification accelerating, scientists, resource managers, and policymakers recognize the urgent need to strengthen the science as a basis for sound decision making and action.
Which of the following graphs shows the general relationship between pH and acidity as described in the passage?
Adapted from "What is Ocean Acidification?" NOAA Pacific Marine Environmental Laboratory Carbon Program. NOAA. Web. 22 Apr. 2015. http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F.
The Chemistry
When carbon dioxide
Since the beginning of the Industrial Revolution, the pH of surface ocean waters has fallen by 0.1 pH units. Since the pH scale, like the Richter scale, is logarithmic, this change represents approximately a 30 percent increase in acidity. Future predictions indicate that the oceans will continue to absorb carbon dioxide and become even more acidic. Estimates of future carbon dioxide levels, based on business as usual emission scenarios, indicate that by the end of this century the surface waters of the ocean could be nearly 150 percent more acidic, resulting in a pH that the oceans haven’t experienced for more than 20 million years.
The Biological Impacts
Ocean acidification is expected to impact ocean species to varying degrees. Photosynthetic algae and seagrasses may benefit from higher
Ocean Acidification: An Emerging Global Problem
Ocean acidification is an emerging global problem. Over the last decade, there has been much focus in the ocean science community on studying the potential impacts of ocean acidification. Since sustained efforts to monitor ocean acidification worldwide are only beginning, it is currently impossible to predict exactly how ocean acidification impacts will cascade throughout the marine food chain and affect the overall structure of marine ecosystems. With the pace of ocean acidification accelerating, scientists, resource managers, and policymakers recognize the urgent need to strengthen the science as a basis for sound decision making and action.
Which of the following graphs shows the general relationship between pH and acidity as described in the passage?
The passage describes the relationship as logarithmic. If you were unsure of what a logarithmic graph looks like, you could use the fact that a 0.1 pH change "represents approximately a 30 percent increase in acidity" as described by the passage, so none of the linear choices make sense and the U-shaped curve doesn't fit this relationship either, leaving you with the correct choice.
The passage describes the relationship as logarithmic. If you were unsure of what a logarithmic graph looks like, you could use the fact that a 0.1 pH change "represents approximately a 30 percent increase in acidity" as described by the passage, so none of the linear choices make sense and the U-shaped curve doesn't fit this relationship either, leaving you with the correct choice.
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