PSAT Reading Question 287: Answer and Explanation

Question: 287

Based on the graphs, which of the following groups includes the greatest biomass of herbivorous fish?

• A. Detritivores when the water temperature is 28 degrees Celsius
• B. Parrotfishes when there are 0 humans per hectare of reef
• C. Browsers and parrotfishes when there are 40 humans per hectare of reef
• D. Browsers when the water temperature is 20 degrees Celsius

Correct Answer: D

Explanation:

D

The question asks which group includes the greatest biomass of herbivorous fish. Work through each answer choice using the figures. Figure 2 shows a biomass of about 1.8 for detritivores at a water temperature of 28 degrees Celsius. Figure 1 shows a biomass close to 1.5 for parrotfishes when there are 0 humans per hectare of reef. Figure 1 shows a biomass close to 0 for browsers and parrotfishes when there are 40 humans per hectare of reef. Figure 2 shows a biomass of about 3 for browsers when the water temperature is 20 degrees Celsius. Since browsers when the water temperature is 20 degrees Celsius have the highest biomass among the answer choices, keep (D) and eliminate (A), (B), and (C). The correct answer is (D).