Using current genetic engineering techniques can provide potential benefits for parents, including A.
eliminating all genetic diseases from their child.
B.
conceiving a child who is a bone marrow match to a living child.
C.
cloning a parent to produce a child identical to the parent.
D.
producing only children with blonde hair.

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.