Official Explanation
Snakes tend to be stationary creatures. Why? They stay put because a particular locality meets their needs: it provides or offers them food and shelter.
Look at the other answer choices. Can you rule out any of them? Denies, disallows, and withholds are all negative terms; none of them seem appropriate in this context. After all, if a locality denied or disallowed the snakes food and shelter or withheld food and shelter from them, that would not be an inducement or incentive for the snakes to stay put. Likewise, constitutes (composes; establishes) does not seem appropriate in the context. It feels awkward, even ungrammatical (the verb does not normally take an indirect object).
Only affords is left. Here it clearly is not used with its primary meaning, “to be able to meet the expense of,” as in affording to buy a new car.
Try to think of other contexts for afford. “It affords me great pleasure to be here.” “Gustavo’s Facebook entries afford us a glimpse into the daily life of a musician on tour.” These sentences use afford with a secondary meaning: to give, offer, or provide. The correct answers to this sentence equivalence question are affords and provides.
Answer: A,C