A study question tests what you can conclude by comparing groups. Start by naming each group and what the researchers counted in each. Ask what stayed alike and what differed, because a cause shared by both groups can’t explain their difference. Then apply any stated rule to those results, especially when the text says something is needed for growth. Predict only what the results support, because a possible cause isn’t always a proven one.
Hints
- Hint 1
Compare the logged and unlogged plots. Put the adult counts and seedling counts side by side.
- Hint 2
Look back at what the seeds need to germinate. How could that rule help explain the difference between the plots?
Step-by-step
Compare the plots, then apply the rule
Step 1Separate adults from seedlings
In logged plots, the botanists found far fewer seedlings than in nearby unlogged plots, even though adult orchid numbers were similar in both areas. What must the ending explain? The blank asks what logging likely did, so we need a cause of the seedling gap that fits the similar adult counts. The gap is in new seedlings, not in the number of adult orchids.
- Step 2
Use the rule about sprouting
The seeds germinate only in the presence of a specific soil fungus. What does only tell us? The fungus must be present for seeds to sprout, so fewer seedlings could result if that fungus became less available. The text doesn’t say how much fungus was present, so this remains a likely explanation rather than proof. Let’s stick to what the text supports: logging may have affected what the seeds need to sprout.
- Step 3
Test the proposed causes
The claims about widespread harvesting of adult orchids and a herbivore that feeds primarily on adult orchids focus on harm to adults, which the similar adult counts don’t support. The sunlight claim points to more seedling growth, but the logged plots had far fewer seedlings. The choice with disrupted the soil conditions explains how logging could affect the specific soil fungus and make it harder for seeds to sprout. Choice C.