ACT science practice test 7

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.


The oceans of Earth are exposed to various climates and consequently have different physical properties. Deep oceans can be divided into zones based on temperature gradient and penetration of sunlight. Figure 1 shows the zones of a typical deep-water ocean, the depth of the zone boundaries in meters (m), and the overall pressure at those depths in kilopascals (kPa). Figure 2 shows the water temperature in degrees Celsius (°C) in warmer tropical oceans and cooler temperate oceans at varying depths. Sound waves are used to measure water temperature at depth, and readings from two different ocean regions are recorded in Table 1.

Figure 1

Figure 2

1. According to

Figure 1, the regions of several ocean zones overlap. Which of the following pairs of ocean zones share part of a common depth range?

A. Bathypelagic and mesopelagic
B. Bathypelagic and epipelagic
C. Epipelagic and thermocline
D. Epipelagic and mesopelagic

2. According to

Figure 1, an oceanographic reading taken at a total pressure of 1,200 kPa is most likely from which of the following zones?

F. Abyss
G. Continental rise
H. Mixed
J. Continental shelf

3. According to

Figure 2, a sonographic measurement of temperature would be unable to distinguish the difference between tropical and temperate oceans at which of the following depths?

A. 250 m
B. 500 m
C. 625 m
D. 750 m

4. According to

Table 1, the relationship between depth and ocean temperature is best described by which of the following statements?

F. The water temperature increased with increasing depth in Region 1 only.
G. The water temperature decreased with increasing depth in Region 1 only.
H. The water temperature increased with increasing depth in Region 2 only.
J. The water temperature decreased with increasing depth in Region 2 only.

5. According to

Figure 1 and

Table 1, if water temperature measurements were taken at depths greater than 79.5, the total pressure at those depths would most likely:

A. decrease to less than 101 kPa.
B. increase to more than 900 kPa.
C. stay at 900 kPa.
D. increase to 101 kPa.

Although many forms of bacteria are helpful for human health, they can also cause illness and even death from severe infections. Antibiotics are a class of medicines used to combat bacterial infections. Bacteriostatic activity inhibits bacteria cell division and bactericidal activity kills bacterial cells. Both actions eliminate populations of bacteria over time. Several classes of bacteriostatic and bactericidal antibiotics are described in Table 1.

The effectiveness of several antibiotics against a bacterium known to cause common skin infections was tested. Drugs were introduced to the bacterial culture by themselves or in combination with sulfamethoxazole (forming SMX compounds). The effectiveness of these antibiotics at eliminating the responsible bacterium is shown in Figure 1.

Figure 1

6. According to the information in

Table 1 and

Figure 1, what can be concluded about the use of sulfamethoxazole as an antibiotic for common skin infections?

F. Using sulfamethoxazole 800 mg is ineffective as an antibiotic.
G. Increasing the dosage of sulfamethoxazole decreases its overall effectiveness as an antibiotic.
H. As an antibiotic, the mechanism of action of sulfamethoxazole is unknown.
J. Compounding antibiotics with sulfamethoxazole increases their effectiveness against common skin infections.

7. According to

Figure 1, if an investigator administered a sulfamethoxazole dose of 600 mg, 20% of the original bacteria would remain after a treatment interval:

A. greater than 120 min.
B. between 90 and 120 min.
C. between 60 and 90 min.
D. between 30 and 60 min.

8. After treatment of a bacterial culture similar to that in the passage with 250 mg of penicillin for 2 hours, the culture will probably contain:

F. less bacteria overall, but most will have survived.
G. less bacteria overall, and most will have been killed.
H. the same amount of bacteria overall, and most will have survived.
J. the same amount of bacteria overall, and most will have been killed.

9. Is the statement “antibiotics compounded with sulfamethoxazole are more effective against common skin infections than when administered alone” supported by the information shown in

Figure 1, and why?

A. No, because penicillin is more effective against a common skin infection bacterium than sulfamethoxazole 400 mg.
B. No, because azithromycin is more effective against a common skin infection bacterium than SMX/azithromycin.
C. Yes, because sulfamethoxazole 800 mg is more effective against a common skin infection bacterium than SMX/azithromycin.
D. Yes, because SMX/doxycycline is more effective against a common skin infection bacterium than doxycycline.

10. According to the passage, the most effective antibiotic against bacteria is one that results in the:

F. lowest percentage of bacterial elimination in the shortest treatment interval.
G. lowest percentage of bacterial elimination in the longest treatment interval.
H. greatest percentage of bacterial elimination in the shortest treatment interval.
J. greatest percentage of bacterial elimination in the longest treatment interval.