ACT science practice test 80

Directions: Each passage is followed by several questions. After reading a passage, choose the best answer to each question and fill in the corresponding oval on your answer document. You may refer to the passages as often as necessary.

You are NOT permitted to use a calculator on this test.


Air permeability is defined as the ability of soil to transmit air through interconnected air-filled pores under an imposed air pressure gradient. Air permeability is a function of volumetric water content, porosity, pore size distribution, and pore geometry. Scientists used a soil corer air permeameter (SCAP) to digitally measure the flow rates of air through desert soil under low-pressure gradients. The SCAP measured air permeability both in situ, with the instrument inserted in the soil and ex situ, after the soil corer had been removed from the soil. Figures 1 and 2 display the results of field testing conducted at two of the four sites in Arizona, over the course of three months. The porosity of the soil at each site is displayed in Figure 3. Figure 4 shows the relationship between the air pressure used and the flow rate of the air for each site.

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Figure 1

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Figure 2

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Figure 3

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Figure 4

1. According to Figure 2, the air permeability measured ex situ in October was closest to which of the following?

F. 5 μm2
G. 15 μm2
H. 20 μm2
J. 30 μm2

2. Based on Figure 4, if the air permeability had been tested at Site 1 using 800 Pa, the flow rate would most likely have been closest to which of the following?

A. 0.5 m3/s
B. 0.6 m3/s
C. 0.4 m3/s
D. 0.3 m3/s

3. Which of the following is the most likely explanation for the difference in air permeability at Site 1 versus Site 2?

F. The overall air permeability is higher at Site 1 due to the lower porosity of the soil.
G. The overall air permeability is higher at Site 2 due to the higher porosity of the soil.
H. The overall air permeability at Site 2 is higher because less pressure was used when testing the soil.
J. The overall air permeability at Site 2 is higher because more pressure was used when testing the soil.

4. If the data in Figures 1 and 2 is typical of air permeability measurements, one would most likely make which of the following conclusions about air permeability in situ versus ex situ?

A. The permeability will always be higher ex situ than in situ.
B. The permeability will always be lower ex situ than in situ.
C. Water permeability is higher than air permeability in situ and ex situ.
D. At high pressures, air permeability is greater in situ than ex situ.

5. According to Figure 1, which of the following statements is most accurate regarding permeability during the month of November?

F. Permeability was lower than in previous months.
G. Permeability was highest for air measured while the SCAP was still inserted in the ground.
H. Permeability was highest for air measured after the SCAP had removed a core from the soil.
J. Permeability was highest for water.

Scientists studying sucrose examined oranges and lemons to determine how the two fruits form and synthesize sucrose. Studies were conducted both on extractions from the fruits and on small, intact fruits.

Study 1

Mature lemon and orange fruits were obtained and then juiced by hand. Formation of fructose was determined using two portions of the fruits: the juice, and the particulate sediment. The results are shown in Table 1.

Table 1—Formation of Sucrose by Fructose Reaction

PreparationSucrose Synthesized (μ moles)
Oranges
Juice
Particulate sediment


0.12
0.9
Lemons
Juice
Particulate sediment


0.4
0.17

Study 2

Scientists found lemons of varying ages from the same fruit grove. Each piece of fruit was cut into sections, and various tissue samples were isolated for testing. The three tissue types tested were the flavedo (colored, outer layer of the peel), the albedo (white peel layer), and the vesicle (fleshy part of the fruit). The results of the formation of sucrose in lemons are shown in Figure 1.

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Figure 1

Study 3

Whole fruits (each weighing approximately 5 g) were tested and then cut into sections to measure sucrose activity in the various tissues. Figure 2 displays the results.

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Figure 2

6. Based on Figure 1, which type of lemon tissue forms the most sucrose?

A. The albedo tissue in a large lemon
B. The albedo tissue in a small lemon
C. The flavedo tissue in a large lemon
D. The vesicles in a small lemon

7. According to the results of Study 2, as fruit size increased, the sucrose found in the vesicles:

F. increased only.
G. increased, then decreased.
H. decreased only.
J. decreased, then increased.

8. Based on the results of Study 3, the largest difference in sucrose activity was found in:

A. oranges between the flavedo tissue and the albedo tissue.
B. oranges between the albedo tissue and the vesicle tissue.
C. lemons between the flavedo tissue and the vesicle tissue.
D. lemons between the flavedo tissue and the albedo tissue.

9. Based on the results of Study 1, which of the following is most accurate about the formation of sucrose?

F. Orange juice is more effective at forming sucrose than lemon juice.
G. Orange juice is less effective at forming sucrose than lemon juice.
H. Lemon juice and orange juice are equally effective at forming sucrose.
J. Lemon juice forms less sucrose than lemon particulate sediment.

10. Assume Study 2 was repeated using oranges instead of lemons. Based on the information presented in Figures 1 and 2, and assuming that the fruits used in Study 3 were 30 mm in diameter, which of the following would most likely be the sucrose formation (as a percent of total activity) in the albedo tissue of the oranges?

A. 0
B. 3
C. 9
D. 20

11. Based on the results of Study 2, which statement most accurately summarizes the formation of sucrose in lemons?

F. The fleshy part of the lemon formed the majority of the sucrose.
G. The colored outer layer of the peel does not form any sucrose.
H. The part of the lemon that forms the most sucrose is dependent on the size of the lemon.
J. More sucrose is formed in the white peel layer of a lemon than anywhere else.