Question

red giants are ancient stars, near the end of their life cycle; they are no longer in their \main sequence\ where they burn hydrogen. these are the large stars in pale pink. how do they compare in temperature and luminosity to the main sequence stars they evolved from? they are significantly brighter, but cooler or roughly equal in temperature. they are dimmer, but hotter. they are dimmer and also cooler. they are much brighter, and also much hotter. rewatch submit

Explanation:

Red - giants are large and have expanded. Their surface area increases while the energy output per unit area (related to temperature) may decrease or stay similar. Their large size makes them more luminous overall compared to their main - sequence counterparts.

Answer:

They are significantly brighter, but cooler or roughly equal in temperature.