Why does a red giant grow in radius?
A) The star's core expands, pushing out its envelope as well.
B) The star's envelope heats up.
C) The opacity in the outer layer increases.
D) The star's gravity decreases because of mass loss during fusion.

Question

Quizplus · Accepted Answer

As a red giant's core contracts and heats up, the outer layers expand due to increased opacity, causing the star to grow in radius.

Why Does a Red Giant Grow in Radius