If a star is moving away from you how does it affect the wavelength of the light waves that reach you?

This is called the Doppler Effect. It is the alteration in frequency of a wave when the source, the light waves in this situation, and the observer are moving away from each other. The reason for stars to appear further from the observer is the constant expansion of the universe.

The answer is b.the gaseous state is electrically positive, while the plasma state is electrically negative.