Answer:
Stars form inside relatively dense concentrations of interstellar gas and dust known as molecular clouds.
Star formation begins when the denser parts of the cloud core collapse under their own weight/gravity. These cores typically have masses around 104 solar masses in the form of gas and dust.
A star during most of its life is called a "main-sequence star". It consists of a central core, convective and radiative zones, the photosphere, the chromosphere, and the corona. The core of the star is where all the nuclear fusion reactions occur to power the star.
