Question

How does the amount of hydrogen gas in a star change over its lifetime?

A. It increases because hydrogen atoms are formed in a red giant when helium fuses.
B. It decreases because hydrogen atoms become fused together to form helium atoms.
C. It fluctuates up and down because the star performs different types of nuclear fusion at different life stages.
D. It stays the same because hydrogen atoms are gained from space to replace the atoms lost during nuclear fusion.

Answer 1

B. It decreases because hydrogen atoms become fuses together to form helium atoms