What mechanism provides the necessary outward force to counteract gravity during a star's main sequence life?

Answer

The thermal pressure from hydrogen fusion in the core pushing outward.

During its main sequence, a star achieves equilibrium where the inward pull of gravity is balanced by the thermal pressure generated by ongoing hydrogen fusion occurring in the core.

What mechanism provides the necessary outward force to counteract gravity during a star's main sequence life?
evolutionstarsupernovaastrophysicsmass