Given below are the steps in the life cycle of a massive star . Using the information about life cycle of stars , arrange the steps in the correct order of their occurrence :
a red giant forms when the stars hydrogen level drops
if it is a massive star , a neutron star is formed . if it is super massive star , a black hole is formed
a main sequence star that can live for millions or even billions of years gets formed
gravity pulls hydrogen gas together to form a cloud
a supernova occurs
nuclear fusion occurs causing the star to glow .