What is sodium fusion

The halogens, nitrogen and sulphur are covalently bonded to the organic compounds. In order to detect them, the elements need to be converted into their ionic forms. This is done by fusing the organic compound with sodium metal. ... The extract is called sodium fusion extract or Lassaigne's extract.

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.