Look at the picture below. What kind of reaction is being used to extract copper from its salt solution using the iron nail?

Displacement reactions

Explanation:

Displacement reactions are easily seen when a salt of the less reactive metal is in the solution. During the reaction: the more reactive metal gradually disappears as it forms a solution.

in the analysis of systems that involve fluid flow, we frequently encounter the combination of properties u and pv.

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.