The claim we are asked to support in this question,
Jude.m.stone@gmail.com , is not about how recent cooking is, but whether cooking has been around long enough to impact human evolution. You have to focus on the issue of human evolution to strengthen that claim. Even if we had said that cooking had been around for a million years, we would still need evidence that human evolution could have been affected in that timeframe, and answer D does nothing to connect those ideas. So what if there's more strontium in our bones? So what if we began to eat more plants? The question is whether any of that caused us to adapt in some way! Has cooking had time to change us?
I notice that you tried to help the answer by making some assumptions, such as:
So because D said that evidence shows that early humans show a spike in the quantity of plants they ate
Never make any assumptions when analyzing the answers! The correct answer is correct without our help, and as soon as you try to help an answer be better by adding your assumptions, you're almost certainly rationalizing why a bad answer might somehow be acceptable.
As to your last question, context is almost always an important consideration in RC questions. What was the sentence referring to? What later statements helped clarify or qualify that sentence? What was the author's purpose in that paragraph? Look beyond just the words themselves to see what else you might need to know in order to answer the question.
Adam M. Tyson
PowerScore LSAT, GRE, ACT and SAT Instructor
Follow me on Twitter at
https://twitter.com/LSATadam