Acell with normal tonicity is placed in a 200 mm nacl solution. this solution is and the cell will

The concentration of a cell is generally 0.15 M  (0.9 % NaCl)

As given the solution has concentration = 200mm = 0.02 M

This concentration of solution is less than the concentration of cell

Hence solution is hypotonic (less concentration) and cell will be hypertonic

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.