ACT Science Practice Test 97

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.


PASSAGE V

Aphids are small plant-eating insects known to feed on rosebushes. In the cultivation of roses, certain pesticides are often applied when the presence of aphids is detected. However, sometimes the flowers that are treated with the pesticides are not as vibrant or fragrant as those that did not receive the pesticide treatment. Two experiments were conducted to study the effects of certain pesticides on rosebushes.

Experiment 1

A gardener filled 125 pots with Soil Type 1. No pesticide was added to the soil in 25 pots. The other pots were divided into four groups of 25 and the soils in each group were treated with 5, 15, 25, or 35 parts per million (ppm) of either Pesticide A or Pesticide B. All other factors were held constant. Fully grown rosebushes with buds but no flowers were planted after the pesticide was placed in the soil. After 30 days the rosebushes were uprooted, sun-dried, and the total number of petals produced by the bushes was counted. The results are shown in Table 1.

Experiment 2

Experiment 1 was repeated with 100 pots of Soil Type 1 and 100 pots of Soil Type 2. The same pesticide doses and type and number of rosebushes were used. All other factors were held constant. After 30 days the rosebushes were uprooted and weighed. The results are shown in Table 2.

Information on the composition of the two soil types used is given in Table 3.

1. Which of the following sets of rosebushes served as the control in Experiment 1?

F. Rosebushes grown in soil with no pesticide added
G. Rosebushes grown in soil treated with 15 ppm of Pesticide A
H. Rosebushes grown in soil treated with 15 ppm of Pesticide B
J. Rosebushes grown in soil treated with 35 ppm of Pesticide A

2. Which of the following, if true, best explains why the pesticides were applied to the soil as opposed to being placed directly on the rosebushes?

A. Pesticides are never applied to the plants when treating aphids or other pests.
B. Aphids are not affected when a pesticide is applied directly to the soil.
C. The experiments were testing how water levels affect growth patterns.
D. Rosebushes generally die when pesticides are directly applied to them.

3. Assume that there is a direct correlation between plant weight and the number of petals on the flowers. If a rosebush was grown in Soil Type 2, one would predict that the number of petals would be lowest under which of the following conditions?

F. Pesticide B at 35 ppm.
G. Pesticide A at 35 ppm.
H. Pesticide B at 25 ppm.
J. Pesticide A at 15 ppm.

4. Assume that a rosebush was grown in soil treated with varying doses of a third pesticide (Pesticide C). Based on the results of the experiments, what prediction, if any, about the effect of Pesticide C on the growth of this rosebush can be made?

A. Pesticide C would have no impact on the growth of the rosebushes.
B. Pesticide C would interfere with the growth of these rosebushes by making them smaller.
C. Pesticide C would interfere with the growth of these rosebushes by making them less fragrant.
D. No prediction can be made on the basis of the results.

5. The results of Experiment 2 indicate that, at every pesticide dose, average plant weight was lowest under which of the following conditions?

F. Pesticide B and Soil Type 1
G. Pesticide A and Soil Type 1
H. Pesticide B and Soil Type 2
J. Pesticide A and Soil Type 2