At what stage of its life does a star pass through the protostar phase?
A) When it is expanding in size as a red giant or supergiant
B) Wfter all nuclear reactions have ended in its core
C) Before nuclear reactions begin in its core
D) While it is converting hydrogen to helium in its core

Question

Quizplus · Accepted Answer

The protostar phase occurs before nuclear reactions begin in a star's core, during the stage when the star is still gathering mass and contracting under the force of gravity.

At What Stage of Its Life Does a Star Pass