Question

question 42 when any main - sequence star (low - mass or high - mass) exhausts its core hydrogen fuel supply the core shrinks & heats up while the rest of the star expands into the giant phase. the entire star shrinks in size & becomes a white dwarf. the star undergoes a helium flash. the core immediately fuses its helium into carbon.

Explanation:

When a main - sequence star exhausts its core hydrogen, the core's pressure support from hydrogen fusion is lost. Gravity causes the core to shrink, which increases its temperature. The outer layers of the star expand due to the increased energy coming from the heating core, entering the giant phase.

Answer:

the core shrinks & heats up while the rest of the star expands into the giant phase.