Explain the concept of “survival of the fittest.”

The Definition Of Survival of the Fittest is:

the continued existence of organisms that are best adapted to their environment, with the extinction of others, as a concept in the Darwinian theory of evolution.

it's basically postulating that those who are eliminated in the struggle for life are unfit for the challenge and opportunity.

the unequal cytoplasmic division that  results  in  one egg  and three polar bodies ensures that a fertilized  egg has  ample nutrients  forits journey  to  the uterus.

the answer is cell division : )