Read this excerpt from "Why Are They Called Black Holes?" After many millions or billions of years, the star runs out of hydrogen and energy. Then the star "dies" and collapses into a dense little ball with tons of gravity. Albert Einstein’s theory of relativity predicted that black holes would have to exist if a dead star had enough gravity. Using Einstein's theory, astronomers calculated that if a star more than three times as heavy as our sun died, the force of gravity pulling matter in could overwhelm any other force pushing matter out.

In this excerpt, the author makes a connection between a scientific theory and

the calculations that scientists make.
the beginning of a star's existence.
the idea that all things live and die.
the question of why gravity exists.

fire could start, buildings collapsing, and ash falling from the sky.

explanation:

this is because the buildings or plants could catch on fire and the buildings would most likely collapse. lastly ash would fall because all the burning would cause ash to fall from the sky.

hope this .

- aluminum and copper chloride.

- the chloride ion to separate the aluminum from the oxygen so that the aluminum can react with the copper ions (and the water molecules).

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.