Which of these is the beginning of the life cycle of stars with different initial masses? a red giant
b supernova
c nebula
d blackhole

The correct answer is C. Nebula

Explanation:

A star is one astronomical object mainly composed of plasma and that different to planets, asteroids or other astronomical objects is luminous. An example of this is the Sun which is the center of our solar system. In terms of life cycle, the first stage of any star despite its size is called the Nebulae that is a cloud of gas and other materials, which leads after some time to stars of different sizes; additionally, in subsequent stages a small star will become a red giant and later a planetary nebula and finally a white dwarf as the star dies, while a massive or big star becomes a red supergiant, then turns into a supernova and  finally becomes  black hole or a neutron star; although all these processes take a long time. Therefore, the one that is the beginning of the life cycle of stars with different masses is the Nebula.

i thinking chemical change