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?

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.

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.

A new star is observed. Which of the following pieces of information is necessary to find out how far away it is?

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?

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.

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.

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.

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.

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 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.

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.

If true, which of the following could serve as counter-evidence to the information provided in the passage?