Another mechanism for evolution is natural selection, which occurs when populations of organisms are subjected to the environment. The fittest creatures are more likely to survive and pass their genes to their offspring, producing a population that is better adapted to the environment. The genes of less-fit individuals are less likely to be passed on to the next generation. The important selective force in natural selection is the environment.
Metaphase is the stage in which pairs of chromatids line up on the equatorial plate
Centrioles migrate to opposite sides of the cell during prophase.
In anaphase, the chromosomes arrive at the opposite poles of the cell.