If you start with a higher pressure of reactant, the equilibrium constant will be larger?

Equilibrium constants aren't changed if there is a pressure

change of the system.

The only a change of temperature changes an equilibrium constant of a reaction.

Explanation:

let that person have a turn to speak : )

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.