Question

ch. 24.1 guided reading
how do we know the story of stellar evolution if stars can exist for millions, billions, or tens of billions of years?

Explanation:

Astronomers study different stars at various stages in clusters and use theoretical models based on physics principles like nuclear - fusion and gravitational equilibrium. By observing star clusters with stars of different ages and analyzing their properties such as mass, temperature, and luminosity, we piece together the story of stellar evolution.

Answer:

Astronomers study star clusters and use theoretical models.