How is the thermonuclear burning phase during a star's stable life characterized regarding energy?

Answer

Exothermic, releasing required energy.

This thermonuclear burning phase is exothermic, meaning it releases the energy necessary to counteract the crushing force of gravity and keep the star stable temporarily.

How is the thermonuclear burning phase during a star's stable life characterized regarding energy?
ElementastronomystarsupernovaFusion