What is happening inside a star while it expands into a subgiant?
A)It is fusing hydrogen into helium in the core.
B)It is fusing hydrogen into helium in a shell outside the core.
C)It is fusing helium into carbon in the core.
D)It is fusing helium into carbon in a shell outside the core.
E)It is not fusing any element;it is contracting and heating up.

Question

Quizplus · Accepted Answer

As the star begins to run out of hydrogen fuel in its core, it begins to fuse hydrogen into helium in a shell surrounding the core. This causes the outer layers of the star to expand and cool, leading to the star becoming a subgiant.

What Is Happening Inside a Star While It Expands into a Subgiant