What does the Hertzsprung-Russell diagram tell us about stars and their life cycles?

A. Stars enter the white dwarf stage once they have exhausted the hydrogen fuel in their cores and have
started to burn helium and other heavier elements

B. Every star goes through specific evolutionary stages dictated by its internal structure and how it produces
energy

C. Stars evolve, typically moving through the H-R diagram in the sequence white dwarf, main sequence, red
giant.

D. Red giants have low surface temperatures and high luminosities.

E. Stars spend about 90% of their lives burning hydrogen into helium in their cores as main sequence stars.

F. Our Sun would be classified as a red giant or letter B in the H-R diagram.