The free energy of an object is the total available energy that the object possesses

true or false?

That is True.

Explanation:

You can only take the amount of energy that the object has and no more. Once you take all the energy there is no more energy to be taken.

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.