ACT Science : Biology
Study concepts, example questions & explanations for ACT Science
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Example Questions
Example Question #91 : How To Find Data Representation In Biology
Background
Plants take in nutrients through extensive root systems, as well as from the air through leaves or needles. Many coniferous evergreens are able to survive for a few weeks after being cut down due to their water-saving needles.
A group of students investigated the properties of several types of coniferous evergreens once they had been extracted from their environments. The students compared the length of time before needles (modified leaves) began to fall from the trees. They placed recently severed, seven-foot trees in spaces with controlled temperature and environmental conditions, and then monitored them closely over several days.
Experiment 1
The students placed representative samples of several varieties of coniferous evergreen in a controlled environment: 20°C, 1 atm, and 35% humidity. They recorded the number of days before needles began to fall for each species.
Results: Experiment 1
|
Species Name |
Days Before Needle Drop |
|
Grand Fir |
28 |
|
Virginia Pine |
29 |
|
Douglas Fir |
35 |
|
Pinyon Pine |
32 |
Experiment 2
The students used the Douglas Fir to conduct a second experiment. They placed new trees in enclosed spaces, varied the temperature and humidity of the trees' environments, and recorded the number of days before needles began to fall.
Results: Experiment 2
|
Temperature |
Humidity |
Days Before Needle Drop |
|
20°C |
55% |
37 |
|
30°C |
55% |
33 |
|
20°C |
45% |
36 |
|
30°C |
45% |
32 |
|
20°C |
65% |
39 |
|
30°C |
65% |
35 |
Based on the data represented in this study, how might coating the needles with wax influence the results of Experiment 2?
It would increase humidity's effect.
It would decrease humidity's effect.
It would increase temperature's effect.
It would decrease temperature's effect.
Not enough information is provided to support any of these claims.
Not enough information is provided to support any of these claims.
Although we might infer that coating the needles with wax could inhibit the uptake of water from the environment, we do not have enough information to show interactions with other variables. There is not enough information in either the results or the background to establish a relationship between wax coating and either temperature or humidity.
Example Question #91 : Biology
A mycologist performed an experiment to determine the effect of methanol on the mold Neurospora crassa.
1,500 Neurospora spores were divided evenly into five groups of three large glass test tubes each. Then each test tube was filled with 5.0 mL of liquid nutrient solution and either 0 mL, 0.5 mL, 1.0 mL, 1.5 mL, or 2.0 mL of methanol. The tubes were placed in an incubator at 28oC overnight to germinate, and then their aerial growth was marked beginning the next morning and every twelve hours thereafter for two days.
Table 1 shows the average growth data with 
In general, the results of the study suggest that Neurospora cultures prepared in liquid media can tolerate at least how many milliliters of methanol and still grow?
Table 1 shows that the mold cultures still grow when 0.5 mL, 1.0 mL, or 1.5 mL methanol is added. The cultures do not grow when 2.0 mL of methanol is added. Therefore, the study suggests that the largest amount of methanol that the strains can tolerate is 1.5 mL.
Example Question #93 : How To Find Data Representation In Biology
A science class has been assigned a group project. Three different groups have been asked to plant a small pallet of grass and record growth over the course of 3 weeks. One blade of grass per trial was designated as the blade of grass to measure each week (the grass height for "Week 0" corresponds to the day the grass was planted). Every Monday (including the day it was planted) this same blade of grass is measured and its height (in inches) is recorded in a data table. The data collected by Group 1 corresponds to Table 1, Group 2 corresponds to Table 2, and Group 3 corresponds to Table 3.
Each group had two control conditions and one variable condition. The three conditions are:
- the amount of water given to the grass
- the type of soil the grass was planted in
- the amount of sunlight the grass is exposed to every day
The variables and data collected are as follows:
Group 1 variable: different amounts of water
Trial A - one cup of water is poured on the grass every Monday after measuring
Trial B - two cups of water are poured on the grass every Monday after measuring
Trial C - three cups of water are poured on the grass every Monday after measuring
Group 2 variable: different types of soil
Trial D - standard potting soil is used
Trial E - large rocks are mixed into the standard potting soil before the grass is planted
Trial F - small stones and pebbles are mixed into the standard potting soil before the grass is planted
Group 3 variable: different sunlight exposure
Trial G - the grass is given 3 hours of sun exposure per day
Trial H - the grass is given 6 hours of sun exposure per day
Trial J - the grass is given 9 hours of sun exposure per day
Which of the following are true regarding the growth rate of the grass tested in Trial C from week 0 to week3?
The approximate change in height from week 2 to week 3 is about the same as the approximate change in height from week 0 to week 1
The approximate change in height from week 2 to week 3 is much larger than the approximate change in height from week 0 to week 1
None of these
False; the approximate change in height from week 2 to week 3 is approximately equal to the approximate change in height from week 0 to week 1
The approximate change in height from week 2 to week 3 is much smaller than the approximate change in height from week 0 to week 1
The approximate change in height from week 2 to week 3 is much smaller than the approximate change in height from week 0 to week 1
The change in height from week 2 to week 3 is 
Example Question #91 : Act Science
A science class has been assigned a group project. Three different groups have been asked to plant a small pallet of grass and record growth over the course of 3 weeks. One blade of grass per trial was designated as the blade of grass to measure each week (the grass height for "Week 0" corresponds to the day the grass was planted). Every Monday (including the day it was planted) this same blade of grass is measured and its height (in inches) is recorded in a data table. The data collected by Group 1 corresponds to Table 1, Group 2 corresponds to Table 2, and Group 3 corresponds to Table 3.
Each group had two control conditions and one variable condition. The three conditions are:
- the amount of water given to the grass
- the type of soil the grass was planted in
- the amount of sunlight the grass is exposed to every day
The variables and data collected are as follows:
Group 1 variable: different amounts of water
Trial A - one cup of water is poured on the grass every Monday after measuring
Trial B - two cups of water are poured on the grass every Monday after measuring
Trial C - three cups of water are poured on the grass every Monday after measuring
Group 2 variable: different types of soil
Trial D - standard potting soil is used
Trial E - large rocks are mixed into the standard potting soil before the grass is planted
Trial F - small stones and pebbles are mixed into the standard potting soil before the grass is planted
Group 3 variable: different sunlight exposure
Trial G - the grass is given 3 hours of sun exposure per day
Trial H - the grass is given 6 hours of sun exposure per day
Trial J - the grass is given 9 hours of sun exposure per day
The science teacher offers Group 1 extra credit if they keep recording data for another week. The students in charge of Trial B record the height of the grass on the Monday of week 4 to be 
neither increasing nor decreasing
decreasing only
increasing only
increasing, then decreasing
decreasing, then increasing
increasing, then decreasing
Since each week showed a successive growth in the grass, the data was increasing only. However, the new data point during week 4 showed a grass height that was smaller than the height recorded in week 3. Therefore, the data was decreasing for the final week.
Example Question #92 : Act Science
A scientist discovered a new type of bacteria that can be harmful to humans. The scientist decided to perform an experiment to determine which antibiotics will be able to treat human illnesses contracted from the bacteria. The scientist created four plates that each contain the necessary minerals for the bacteria to growth and placed some of the bacteria on each plate (as seen below in the initial setup). Once the bacteria were placed on the plates, she placed a piece of paper soaked in an antibiotic in the center of each treatment’s petri dish. Each piece of paper was soaked in a different antibiotic. She also constructed a control plate using a piece of paper soaked in saline solution. Three different antibiotics and one control plate without antibiotics were tested. The final results are shown in the provided figure, in which the bacteria is represented by the grey areas.
How can the scientist quantify the amount of bacteria in each plate?
Cannot be determined
Use a ruler to determine the area covered by the bacteria
Determine the transparency in a bacteria filled portion of the plate
Determine the time it takes for all of the plates to become filled with bacteria
Perform a count of the number of bacteria without the aid of a microscope
Use a ruler to determine the area covered by the bacteria
Solve this by using the process of elimination. The individual bacterium cannot be seen without the aid of a microscope; thus, this is not a correct answer. Determining the time it takes for the plates to fill with bacteria will not help in quantifying the amount of bacteria; furthermore, some plates may never completely fill with bacteria. The transparency measurement can potentially return the same results for all plates because the color and concentration of the bacteria is similar across all treatments. Using a ruler will allow the scientist to determine the radius of the bacterial colony and calculate the area of the colony. In the case of streptomycin, the larger circle's area can be calculated and the missing bacteria part can be subtracted from this. This will give the area covered by the bacteria. The area covered by the bacteria quantifies the amount in each treatment.
Example Question #94 : Act Science
A new type of food was developed for feeding salmon. This new “special food” is supposed to increase the weight of the salmon, shorten time to full growth, and increase the life expectancy of the salmon. The food was tested among a variety of salmon: farm raised salmon without treatment, genetically modified salmon (GMO), hormone-treated salmon, and salmon feeding off of the new “special diet.” The results from this experiment were recorded in the provided table. Note that the average weight was recorded after the salmon were fully grown.
All of the salmon are placed together and a child is allowed to take a salmon home to be his pet. What is the maximum life expectancy (in years) that is possible for this child's pet?
7.4 years
4.2 years
6.7 years
3.3 years
Cannot be determined
7.4 years
All of the salmon are mixed together. This means that the child can randomly select a salmon from any of the groups. The maximum possible life expectancy of salmon in the study was recorded in the genetically modified (GMO) group. The maximum life expectancy for this group of salmon is 7.4 years; therefore, 7.4 years is the maximum possible life expectancy of the pet salmon.
Example Question #91 : Biology
Scientists studied five species of birds native to a particular desert. The population of each species was measured at the end of each year over the course of three years that saw dramatic changes in mean daytime temperature. Scientists hypothesized that the changing temperatures would impact the total number of each bird species.
Based on the data, which bird species appeared to do best in the year with the highest mean temperature?
White-winged dove
House finch
Black vultures
Cactus wren
Gila woodpecker
Black vultures
Year 2 showed the highest mean daytime temperature. Of all the birds, the black vultures had their largest population during the warmest year.
Example Question #95 : How To Find Data Representation In Biology
Scientists studied five species of birds native to a particular desert. The population of each species was measured at the end of each year over the course of three years that saw dramatic changes in mean daytime temperature. Scientists hypothesized that the changing temperatures would impact the total number of each bird species.
Which of the following statements is supported by the data provided?
Black vultures are better able to survive in lower temperatures than the other species
White-winged doves are better able to survive in higher temperatures than the other species
Black vultures are better able to survive in droughts than the other species
None of these
White-winged doves are better able to survive through years of heavy rainfall than the other species
None of these
Although the population trends seem to suggest black vultures may better survive in higher temperatures, there is not enough evidence in the provided data to support this conclusion. For instance, in Year 2, the prey of the black vultures may have shown a population spike, providing more food for the vultures to survive. The same goes for the white-winged dove. Despite a correlation shown in the data, there is not enough evidence to conclude a direct link between temperature and population.
Example Question #92 : Biology
Scientists studied five species of birds native to a particular desert. The population of each species was measured at the end of each year over the course of three years that saw dramatic changes in mean daytime temperature. Scientists hypothesized that the changing temperatures would impact the total number of each bird species.
Which bird species appears to be least affected by the change in mean daytime temperature?
House finch
Gila woodpecker
Black vulture
Cactus wren
White-winged dove
Gila woodpecker
Of the five bird species, the population of Gila woodpeckers changes the least (from 300 to 305 to 307) despite the changes in temperature. All four remaining species' populations fluctuate more from year to year.
Example Question #93 : Biology
Scientists studied five species of birds native to a particular desert. The population of each species was measured at the end of each year over the course of three years that saw dramatic changes in mean daytime temperature. Scientists hypothesized that the changing temperatures would impact the total number of each bird species.
Which of the five species survived the best over the entire length of the scientists' observations?
Cactus wren
White-winged dove
House finch
Black vulture
Gila woodpecker
House finch
The problem states the scientists studied the birds over the course of three years, so another way to phrase the question is: "Which species saw the largest increase in population from Year 1 to Year 3?" After reexamining the data to find the answer to this question, the House finch saw the largest increase (from 297 to 370 to 420). No other species saw such a large population increase over the course of the three years. Therefore, the House finch survived the best over the course of the scientists' observations.
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