A steel tank with a volume of 9.583 L contains nitrogen gas under a
pressure of 4.972 atm at 31.8°C. Calculate the mass of nitrogen gas (N) in
the tank.

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.