Question

question 1
what is one difference between main - sequence low - mass stars & main - sequence intermediate & high - mass stars?
low - mass stars spend less time on the main - sequence.
intermediate - & high - mass stars use the cno cycle instead of the proton - proton chain.
low - mass stars will end up with degenerate cores before leaving the main sequence.
only low - mass main sequence stars will turn into red giant stars when leaving the main sequence.

Explanation:

Low - mass stars have lower core temperatures and densities. Intermediate and high - mass stars have higher temperatures and densities which allow the CNO cycle to occur instead of just the proton - proton chain. Low - mass stars spend more time on the main sequence. Both low and high - mass stars can become red giants. Low - mass stars develop degenerate cores after leaving the main sequence.

Answer:

Intermediate - & high - mass stars use the CNO cycle instead of the proton - proton chain.