Draw the structure of tofacitinib with explicitly shown all carbon and hydogen atoms. identify the number of carbon atoms in tofacitinib, and then fill in all of the missing hydrogen atoms that are inferred by the drawing.

The structure of tofacitinib with explicit carbon and hydrogen is the first attached picture.

The number of carbon atoms in tofacitinib are 16.

The molecular formula of tofacitinib is .

The structure of tofacitinib with all the filled hydrogen atoms is the second attached picture.

there are two significant figures.

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.