Command of Evidence
These questions ask which specific piece of evidence — a quotation from a passage, or a data point from a table — actually supports a given claim. Being true isn't enough; it has to support that exact claim.
When on board H.M.S. ‘Beagle,’ as naturalist, I was much struck with certain facts in the distribution of the inhabitants of South America, and in the geological relations of the present to the past inhabitants of that continent. These facts seemed to me to throw some light on the origin of species—that mystery of mysteries, as it has been called by one of our greatest philosophers. On my return home, it occurred to me, in 1837, that something might perhaps be made out on this question by patiently accumulating and reflecting on all sorts of facts which could possibly have any bearing on it. After five years’ work I allowed myself to speculate on the subject, and drew up some short notes; these I enlarged in 1844 into a sketch of the conclusions, which then seemed to me probable: from that period to the present day I have steadily pursued the same object. I hope that I may be excused for entering on these personal details, as I give them to show that I have not been hasty in coming to a decision.
Command of evidence questions come in two flavors. Textual evidence questions ask which quotation from a passage best supports a specific claim — and every answer choice is often a real quotation from the passage, so you can’t just check whether a choice appeared in the text. You have to check whether it supports this particular claim, not just any claim the passage happens to make.
Quantitative evidence questions work the same way, but the evidence is a number from a table or graph instead of a quotation. The trap is the same either way: an answer choice can state something completely true and still be wrong, because it doesn’t actually address the specific claim in the question.
The fastest approach: identify exactly what the claim asserts before you look at the choices, then test each one by asking “does this specific piece of evidence prove that, or does it just say something else that’s also true?”