What is the softening of sharp edges on furniture? Only necessary for high gloss finishes
Only necessary for semi-gloss finishes
A procedure most often performed before the finish is applied
A procedure most often performed after the finish is applied

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.