Hi anksm22,

This is an example of a fill-in-the-blank inference question. We need to understand the logic presented in the prompt and then find an answer that logically completes the last sentence. These types of inference questions can sometimes be tricky.

The Facts:
-Food scarcity or excessive hunting can threaten a population of animals
-Food scarcity: individuals will reach reproductive maturity LATER than OTHERWISE
-Excessive Hunting: individuals who reach reproductive maturity EARLIER will come to predominate.

The Conclusion:
-It should be possible to determine whether mastodons became extinct because of FOOD SCARCITY OR HUMAN HUNTING, since there are fossil remains from before and after mastodon populations declined and ______

The Logic: There appear to be 2 causes that can impact reproductive maturity (food scarcity - leads to LATER maturity; excessive hunting - leads to EARLIER maturity). But earlier or later THAN WHAT? The prompt doesn't establish what the "normal" time is. The prompt concludes that there should be a way to figure out whether mastodons were victims of food scarcity or human hunting though, so I'd be looking for an answer that establishes the "normal" age of maturity of the mastodon. That way, having the fossils will allow us to figure out if they matured earlier or later than normal.

Answer B completes the logic with the piece that we need.

GMAT assassins aren't born, they're made,
Rich