Why will the color of the sun change from yellow to red when it becomes a giant?

Answercolor is related to surface temperature,and a red giant is cooler than a main sequence, medium-sized star like the sun

Without homeostasis, the internal and external environments of organisms would be unbalanced. Too much of one thing can harm, and even kill the organism.
For instance, when dogs are hot, they pant because they don't have sweat glands to maintain homeostasis. However, if the dog could not pant, it would die from its high body temperature.