We are told:
• Elephants spent more time near enclosures with a distressed calf from their own herd than those with a calf from a different herd.
• The conclusion: Elephants are more motivated to care for members of their own herd.
We are asked: Which option would most strengthen this argument?
To strengthen the argument, we want evidence that the elephants’ preference was really due to social bonds (herd membership) — not other possible factors like enclosure setup, calf behavior, proximity, visibility, etc.
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Let’s evaluate each option:
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A. They were encouraged by a familiar zookeeper rather than an unfamiliar one.
❌ Irrelevant. The argument is about calf identity, not human interaction. Doesn’t relate to the core conclusion.
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B. They spent more time at the empty enclosure than at one with a calf from a different herd.
❌ This would weaken the argument. It would suggest that elephants were avoiding unfamiliar calves or were uninterested — not that they cared more about their own. It shifts the explanation toward avoidance, not preference based on herd.
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C. They spent more time when the calf from their herd was in the enclosure than when it was visible but outside the enclosure.
✅ This strengthens the argument. Why?
• It rules out mere visual recognition or familiarity as the full explanation.
• It shows that proximity and access to help mattered — that elephants were more motivated to approach and presumably help their own herd member when they could.
So this supports the idea of a caregiving motivation, specifically when a distressed herd member could be approached — reinforcing the conclusion.
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D. The calf appeared interested in the elephants vs. ignored them.
❌ This puts the focus on the calf’s behavior, not the elephant’s motivation. It introduces a new variable that weakens the causal link between herd membership and the elephant’s choice.
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E. A calf from a different herd was friendly vs. hostile.
❌ Again, this changes the focus from herd membership to the calf’s behavior. The conclusion is about elephants preferring to help their own, not about whether the calf was nice or mean.
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✅ Final Answer: C