what blood vessels and chambers of the heart does a red blood cell pass as it delivers oxygen from the lungs to the brain and return to be oxygenated again.

the answer is option a.

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.