Question

what are three end stages of stars

Answer 1

the expanding star is now called red giant the helium core run out and the outer layer drift of away from the core as a gaseous shell

Answer 2

(1) Stars having initial mass less than 8 times the mass of the sun ultimately become white dwarfs.
(2) Start having initial mass between 8 and 25 times the mass of the sun ultimately become neutron stars.
(3) Star having initial mass larger than 25 times the mass of the sun ultimately turn into black holes.