In a minimum of two sentences, define a red giant and how a red giant forms.

Red Giants are the stars that currently in the late phase of the Stellar Revolution. One of the main features of a red giant is its variations on brightness.
Red Giants are formed because of the constant helium-burning process from the stars (which keep making it bigger and bigger) to the point where it almost ran out of it.

Ithink the answer is d i hope it my friend message me if i’m wrong and i’ll change my answer and fix it for you