Bismuth-212 has a half-life of 60.5 minutes. If you start with 128 grams of Bi-212, how much unchanged Bismuth-212 will be left after 7 half-lives?
(include units with your answer *

wher is the rest of the question

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.