A star is "born" in a large cloud of dust and gas called a nebula
The first stage in a star's life is as a nebula. As the gravitational forces spin faster, the star enters it's second stage, that of a prostar.
stellar nebula
Star Stage - 1955 First Date 1-4 was released on: USA: 30 September 1955
the fourth stage of a star is "supergiant" and its also the hottest stage
Protostar!
Formation of the star out of a giant cloud of gas and dust.
Protostar Stage
It doesn't differ from a star, it is a star and it is the second stage in a stars life after the nebula stage.
Yes black hole is last stage of a star
yes, it is the stage where a star dies and turns into a blackhole
what is the third stage of the star cycle
That would be a nebula, which is an interstellar cloud of hydrogen gas, dust, and plasma. It is the first stage of a star's cycle.