- PowerScore Staff
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- Joined: Sep 06, 2017
As the OP explanation states, (D) has the opposite effect on the argument that (C) has, in that it implies that small animals would have a very similar weight-to-surface area ratio compared to large animals. If this is true, then the stimulus's causal argument goes out the window, because we would have the same effect (very different climbing abilities between large and small animals) without the stimulus's assumed cause (very different weight-to-surface area ratios between large and small animals).
When negated, this should be clear:
Lots of variation in the ratio Ratio differences explain climbing differences
Clearly this doesn't make sense, more variation would be evidence for the conclusion as given, not its negation. Remember when using the Assumption Negation technique you must negate both the answer choice and the conclusion. Contrast this to the negation of (C):
No variation in ratio between large and small animals Ratio differences explain climbing differences
Makes perfect sense, since you can't use something that doesn't exist to explain anything.
Hope this clears things up!