When the core of a star like the sun uses up its supply of hydrogen for fusion, the core begins to contract in size. The gravitational forces becomes strong and cause the star to reduce in size. as the star contracts, the temperature of the star also rises since the heat is distributed inside smaller Volume now.
The offspring of an asexual organism (since asexual reproduction only requires one parent) will be completely identical to the parent, like bacteria or fungi. The offspring of a sexual organism (since sexual reproduction requires two organisms) will be a combination of both parents, like animals or (some) flowers.
Volume will decrease if the heat remains constant
