Assume there are two forces pushing a ball in the same direction: the first force is 5 N and the second force is 10 N. What is the total force being exerted on the ball?

It is 15N in that direction. When it's in the exact same direction, you combine them.

Explanation:

you need to have a picture of the atom that way we can answer it

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.