ACT Science : Earth and Space Sciences

Study concepts, example questions & explanations for ACT Science

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Example Questions

Example Question #151 : Earth And Space Sciences

The chart below depicts the average rainfall by location on the Earth.  Zero degrees latitude corresponds to the equator.  Positive latitudes are north of the equator, while negative latitudes are south of the equator.  A latitude with a magnitude of 90 degrees correlates with one of Earth's poles.  

Rainfall

Which latitude(s) experience(s) an average rainfall of 35 inches?

Possible Answers:

 degrees

 degrees and  degrees

 degrees,  degrees and  degrees

 degrees and  degrees

Correct answer:

 degrees,  degrees and  degrees

Explanation:

On the -axis (Rainfall), locate 35 inches.  Find where the curve of the graph intersects this -coordinate, and find each corresponding -coordinate.  There are three:  , , and 20 degrees.  Although 50 degrees also corresponds to a rainfall of about 35 inches, it is not one of the choices. 

Example Question #152 : Earth And Space Sciences

The chart below depicts the average rainfall by location on the Earth.  Zero degrees latitude corresponds to the equator.  Positive latitudes are north of the equator, while negative latitudes are south of the equator.  A latitude with a magnitude of 90 degrees correlates with one of Earth's poles.

 

Rainfall

The Tropic of Capricorn is about 23.5 degrees south of the equator. Approximately how many more inches of rain does this latitude experience than the North Pole?

Possible Answers:

15 inches

20 inches

25 inches

10 inches

Correct answer:

15 inches

Explanation:

To find out the difference in amount of rainfall between these two latitudes, locate  degrees on the -axis and find the corresponding amount of rainfall on the -axis (25 inches).  Next, find the latitude of the North Pole (90 degrees) and its corresponding amount of rainfall (10 inches).  Finally, subtract the two to find how much more rain the Tropic of Capricorn receives: 

Example Question #152 : Earth And Space Sciences

     Phylogenetics is a tool utilized by evolutionary and molecular biologists to investigate the similarities that exist in the molecular sequences of proteins in varying organisms. The amino acid sequences that build proteins are often used to construct distance matrices that aid in determining evolutionary ties. The study of these matrices helps to expose evolutionary relationships between species that may not have the same phenotypical and existential characteristics.

Study 1

     A researcher decides to compare several bat species to several bird and mammalian species in order to determine which two groups were more closely related. The study compares a ghost bat and a tomb bat with two birds, the pigeon and eagle, and two mammals, the spider monkey and macaque. The researcher compared the amino-acid sequences of beta hemoglobin molecules in order to determine whether bats were more related to birds or mammals. Percent similarities of the data were calculated for comparison purposes (Figure 1).

Figure 1

 

Bat

 

 

Study 2

     A researcher decides to compare a whale to a fish and to several ungulates (hoofed mammals). One set of ungulates that were studied were artiodactyls, meaning they were “even-toed” (hippopotamus and sheep).  The other set of ungulates belonged to a class of mammals known as perissodactyls meaning that they were “odd-toed” (rhinoceros and zebra). The researcher compared the amino-acid sequences of beta hemoglobin molecules in order to determine which species were more related to the Minke whale. Percent similarities of the data were calculated for comparison purposes (Figure 2).

Figure 2

Whale

Based on the information in Study 1, the ghost bat's beta hemoglobin molecular structure is most similiar to which of the following species?

Possible Answers:

Pigeon

Spider Monkey

Eagle

Macaque

Correct answer:

Spider Monkey

Explanation:

The spider monkey is the correct answer because its hemoglobin content is 91.1% similar to the ghost bat indicated by the information in the distance matrix of Table 1. This information is supported by evidence in the passage.

Example Question #153 : Earth And Space Sciences

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.

 

 

Hubble_graph

A star is measured to have a velocity of

How far away is it?

Possible Answers:

3.5 megaparsecs

5 megaparsecs

4.5 megaparsecs

200 megaparsecs

Correct answer:

4.5 megaparsecs

Explanation:

Using the graph, we can see that when the velocity is 300 km/s, the distance will be 4.5 megaparsecs.

Example Question #4 : How To Find Data Representation In Earth And Space Sciences

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.

 

 

Hubble_graph

A star is measured to be 12 megaparsecs away. What should its velocity be?

Possible Answers:

Correct answer:

Explanation:

Based on the graph, an object 12 megaparsecs away should have a velocity a little bit more than 800 km/s. The closest answer is 825 km/s.

Example Question #153 : Earth And Space Sciences

The chart below depicts the average rainfall by location on the Earth.  Zero degrees latitude corresponds to the equator.  Positive latitudes are north of the equator, while negative latitudes are south of the equator.  A latitude with a magnitude of 90 degrees correlates with one of Earth's poles.  
Rainfall

Which of the following best describes the rainfall trend shown in the graph?

Possible Answers:

Rainfall is greatest at Earth’s poles and declines gradually as latitudes approach 0 degrees

Rainfall is greatest near the equator and least at Earth’s poles

Rainfall is greatest in the Northern hemisphere

Peak rainfall occurs at about  degrees

Correct answer:

Rainfall is greatest near the equator and least at Earth’s poles

Explanation:

Peak rainfall occurs around the equator (zero degrees).  The lowest points occur at the poles ( and  degrees).

Example Question #154 : Earth And Space Sciences

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 units expressing the concentration of organic molecules in the samples from Mars and comet are in mg/L.  This unit is most precisely a measure of:

Possible Answers:

Density

Specific Gravity

Mass

Weight

Volume

Correct answer:

Density

Explanation:

The unit mg/L is measuring mass (mg) for a certain number of volume units (L).  As a result, this expression is a measurement of density.

Example Question #7 : How To Find Data Representation In Earth And Space Sciences

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.

Pollen_table_1

Pollen_table_2

Which plant is most tolerant of low levels of precipitation?

Possible Answers:

Plant E

Plant D

Plant A

Plant C

Correct answer:

Plant E

Explanation:

Table 1 lists the types of plants. The third column (labeled "Precipitation") shows the annual precipitation where each plant is commonly found. The lowest annual precipitation is associated with Plant E.

Screenshot_2015-02-16_at_6.23.32_pm

Example Question #8 : How To Find Data Representation In Earth And Space Sciences

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.

Pollen_table_1

Pollen_table_2

The climate associated with Sample 2 could most likely be described as which of the following?

Possible Answers:

Temperature: High

Precipitation: Moderate

Temperature: Moderate

Precipitation: High

Temperature: High

Precipitation: High

Temperature: Low

Precipitation: Moderate

Correct answer:

Temperature: High

Precipitation: Moderate

Explanation:

Information about Sample 2 can be found in Table 2. The most prevalent plant spore for that sample is Plant A.  

Screenshot_2015-02-16_at_6.34.26_pm

Based on the information in Table 1, it is evident that Plant A grows best in high temperatures with moderate rainfall.

Example Question #11 : How To Find Data Representation In Earth And Space Sciences

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.

Pollen_table_1

Pollen_table_2

Assuming Samples 1 through 4 are arranged chronologically, from oldest to most recent, what can be inferred about the change in temperature across the eras that they cover?

Possible Answers:

No pattern

Temperatures decreased

Precipitation increased

Temperatures increased

Correct answer:

No pattern

Explanation:

By identifying the predominant type(s) of plant in each sample in Table 2, you can characterize the temperature of each respective era as Warm, Moderate, or Cool.

Screenshot_2015-02-16_at_9.45.38_pm

As shown above, temperature increases between Samples 1 and 2, decreases between Samples 2 and 3, and finally increases slightly between Samples 3 and 4. Because temperature neither increases nor decreases consistently across each era, no pattern can be identified regarding the trend in temperature change.

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