Question 163·Easy·Inferences
Wild lemurs of Madagascar have a peculiar feeding pattern: they consume large amounts of a certain vine only during the two weeks each spring when the vine produces bright-orange flowers. A team of biologists found that during these weeks, levels of beta-carotene—a compound abundant in the flowers—rose sharply in the lemurs’ blood. The biologists concluded that beta-carotene strengthens the lemurs’ immune systems, which are stressed after the lean dry season.
Based on the biologists’ conclusion, it is most reasonable to infer that lemurs eat the vine’s flowers primarily in order to _____
Which choice most logically completes the text?
For “most logically completes the text” questions, focus on the key conclusion or claim in the passage and ask what follows directly from it, without adding outside ideas. Underline cause-and-effect relationships and timing clues, then eliminate any answer choices that introduce concepts (like competition, scent, or water here) that the passage never mentions. The correct choice will echo or extend the passage’s reasoning in a natural, consistent way.
Hints
Locate the key sentence
Reread the sentence starting with “The biologists concluded that beta-carotene…” and focus on what beta-carotene does for the lemurs.
Use the timing of the behavior
Think about why the lemurs eat the vine only during the two weeks when it has flowers, right after the lean dry season. What condition are they in at that time?
Match benefit, not new ideas
Look for the choice that reflects a direct benefit mentioned in the passage, and be cautious of choices that introduce new topics like competition, scent, or water that the passage never discusses.
Step-by-step Explanation
Restate what the passage tells you
First, summarize the key facts:
- Lemurs eat a certain vine only during a two-week spring period when it produces bright-orange flowers.
- During these weeks, beta-carotene levels in their blood rise sharply.
- The biologists conclude that beta-carotene strengthens the lemurs’ immune systems, which are stressed after the lean dry season.
Understand what the question is really asking
The question says: “Based on the biologists’ conclusion, it is most reasonable to infer that lemurs eat the vine’s flowers primarily in order to _____.”
So you must use the biologists’ conclusion (not background knowledge) to figure out the main purpose of eating the flowers. Ask: If beta-carotene strengthens their stressed immune systems, what is the main benefit to the lemurs of eating these flowers at that time?
Connect the conclusion to the lemurs’ behavior
The timing is important:
- The lemurs eat the flowers only during the weeks when the flowers are present and rich in beta-carotene.
- At that time, their immune systems are stressed from the lean dry season.
From the biologists’ conclusion, you can reason that eating the flowers gives the lemurs a substance that helps their immune systems when they most need it—right after a difficult season.
Eliminate choices that add new, unsupported ideas
Now check each answer choice against the passage:
- Ideas about competition with other species, marking territory with scent, or getting extra water are never mentioned in the passage.
- Only one choice matches the idea that the lemurs are getting something from the flowers that supports their immune systems after stress.
Therefore, the best completion is: “obtain a nutrient that helps them recover from a period of stress.”
State the correct answer
The correct answer is D) obtain a nutrient that helps them recover from a period of stress. This directly follows from the conclusion that beta-carotene in the flowers strengthens their immune systems after the stressful lean season.