Why is one able to walk on red-hot coals without getting one’s feet burned?

You can see examples of this if you happen to drip some water on a hot stove or any hot surface. The water will easily glide around on top of a newly formed layer of air underneath it, like air hockey pucks on an air hockey table.

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.