Answer:
Variations( individuals of a species are not identical), traits are passed from generation to generation, struggle for existence (more offspring are born than can survive) and survival for the fittest(only the survivors of the competition for resources will reproduce).
Step-by-step explanation:
Variations occur within members of a population. These variations arise by chance and from within the individual. Through sexual reproduction these characteristics are transmitted to successive offspring. The offspring by far outnumber the parental generation but only a few survive to adulthood and are able to reproduce. This is due to environment pressures such as predation, diseases and competition for food and breeding sites. In the struggle for existence individuals with advantageous variations are well adapted to the environment.