You have learned how to take steps that are exactly 1m long. You take 12 steps north, then 15 steps north, 35 steps south, 11 steps south, then 16 steps north. What distance have you walked?

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.