The main source of energy for a star as it grows in size to become a red giant is _ _.
A)hydrogen fusion in a shell surrounding the central core
B)hydrogen fusion in the central core
C)gravitational contraction
D)helium fusion in the central core

Question

Quizplus · Accepted Answer

As a star exhausts its hydrogen fuel at its core and evolves into a red giant, the main source of energy becomes hydrogen fusion in a shell surrounding the inert helium core. This process increases the luminosity and size of the star.

The Main Source of Energy for a Star as It