ACT science practice test 11

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.


A scientist studying hemoglobin investigated the impact of temperature and carbon dioxide (CO2) concentrations on the binding capacity of oxygen (O2). The scientist observed the binding of oxygen to hemoglobin molecules as the pressure of oxygen was increased. The temperature and CO2 were varied to identify their direct impact on the binding capacity of O2.

Figure 1 displays the impact of changes in temperature on the binding (percent of hemoglobin saturated) of oxygen. Figure 2 displays the impact of varying carbon dioxide concentrations on oxygen binding. Under normal conditions, the core body temperature is 37°C and has carbon dioxide and oxygen concentrations of 40 mmHg and 100 mmHg respectively.

Figure 1

Figure 2

1. According to Figure 1, if the temperature is 42°C, which of the following changes in pressure of oxygen will cause the least increase in the percent of hemoglobin saturated with O2?

F. 0-15 mmHg
G. 15-30 mmHg
H. 30-45 mmHg
J. 45-60 mmHg

2. According to Figure 1, which of the following sets of temperature and pressure of oxygen results in the lowest hemoglobin saturation with oxygen?

Temperature (°C)

A. 37
B. 37
C. 42
D. 42

3. According to Figure 1, if the pressure of oxygen is 100 mmHg and 65% of hemoglobin molecules are saturated with oxygen then the core body temperature is most likely within which of the following ranges?

F. Less than 30°C
G. 30°C-37°C
H. 37°C-42°C
J. Greater than 42°C

4. Based on Figure 2, if an individual has 70% of his hemoglobin molecules saturated at a pressure of 75 mmHg of oxygen, then the individual's carbon dioxide pressure is most likely closest to which of the following?

A. 30 mmHg
B. 50 mmHg
C. 70 mmHg
D. 90 mmHg

5. According to Figure 2, at a CO2 pressure of 90 mmHg, as the pressure of O2 is increased from 45 mmHg to 90 mmHg, the percent of hemoglobin saturated with oxygen:

F. remains constant, then increases.
G. remains constant, then decreases.
H. increases, then decreases.
J. decreases, then increases.

The magnitude of seismic energy released from an earthquake is often described using the logarithmic and unit-less Richter scale. Originating at the epicenter, seismic energy travels through the earth via waves such as L-waves, S-waves, and P-waves. Earthquakes with a Richter scale magnitude of 5.0 or greater can typically be detected throughout the world. Figure 1 depicts the layers of the earth and typical travel patterns of seismic waves. Table 1 lists characteristics of those seismic waves. Figure 2 shows the number of earthquakes (by magnitude) detected at a particular seismic activity monitoring station in the past 30 years, as well as the percentage probability of future earthquakes (by magnitude) in that same region in the next 30 years.

Table 1
Seismic waveDepth range (km)Crust velocity (m/s)
L-wave0-102.0-4.5
S-wave0-29213.0-4.0
P-wave0-51805.0-7.0

Figure 2

6. Figure 1 defines the mesosphere as a region of the Earth that overlaps which of the following atmospheric layers?

I. Outer core

II. Inner mantle

III. Outer mantle

A. II only
B. I and II only
C. II and III only
D. I, II, and III

7. A series of seismic waves was observed from an observation station. The average crust velocity of these waves was 3 m/s, and their maximum depth occurred in the inner mantle. Based on Figure 1 and Table 1, the seismic waves observed were most likely:

F. L-waves.
G. S-waves.
H. P-waves.
J. K-waves.

8. Given the data in Figure 2, the future probability of an earthquake occurrence decreases by more than half when comparing which of the following 2 Richter scale magnitudes?

A. 5.0 and 6.0
B. 6.0 and 6.5
C. 6.5 and 7.5
D. 7.5 and 8.0

9. According to Figure 2, the probability of a future earthquake occurrence is lowest for which of the following ranges of Richter scale magnitude?

F. 5.5 to 6.0
G. 6.0 to 6.5
H. 6.5 to 7.0
J. 7.0 to 7.5

10. Based on Figure 2, the ratio of Richter scale 5.5 earthquakes to Richter scale 5.0 earthquakes in the last 30 years can be expressed approximately by which of the following fractions?

A.
B.
C.
D.