Why is it, if you were on a train, moving at the speed of light, and you threw a ball into the air, it would fall back into your hand, instead of hitting you? please give a detailed answer!

According to Newton's first law of motion, all bodies will remain in a state  of rest or continue in uniform motion unless acted on by external forces such that the ball will catch up to fall directly in the palm of the hand from where it is released

Explanation:

Given that the ball was already moving along in the train traveling at the speed of light, the horizontal speed of the ball before being released was that of the speed of light such as all objects within the train are traveling with the same speed,  they all act as if they are stationary with respect to one another

When the ball is therefore released into the air, it falls back to the point from where it was released which is directly in the palm of the hand.

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.