Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution.
The death of a small star and a very massive star can be quite dramatically different.
Whereas a small star just shuts off, so to say, and becomes a white dwarf, usually massive stars die creating huge blackholes that can swallow many planets, and everything else around them. Small stars die with a so called "unnova," which means their death is silent. On the other hand, massive stars die creating supernovas, which is a catastrophic explosion.
For speciation to happen reproductive isolation must occur
The correct answer among the choices presented above is option D. The uterus is a pear-shaped muscular organ that houses the developing fetus. It is the organ located in the lower body of a female mammal. It is a major reproductive organ of most mammals.
