1. What stages do stars go through?
by observing different stars in different stages of their formation
Yes.See related question for more information
Gravity doesn't just "affect" the formation of stars; it's just about the only force that CAUSES the stars to form in the first place.
the formation of stars, through the gathering of certain gases. the stars in the big dipper arrangement just happen to look like a big dipper, hence its name
Stars tend to change from one colour to another, as you put it, like a disco ball. This is because the heat inside the star is changing as the stars goes through different growth stages, eventually exploding.
gravitation
Red stars are usually giant stars that are on the brink of death. It is said to be on its last stages of stellar evolution.
after doing all stages, collecting all the gold power stars and all prankster comets, including the special stages, you will be able to collect the green stars, sucks right?
Gravity
When a certain formation of stars comes out.
It causes extinction and it scatters away the shorter wavelengths. Edit : "extinction" of light, of course, in case you were worried.
The Southern Cross