Answer:
1- Presence of phenotypic variation
2- some phenotypic variation due to genetic variation
3- the given trait has an impact on fitness
Explanation:
The evolutionary theory by natural selection proposed by Darwin in his publication “On the origin of species” (1859) is based on a series of assumptions that enable to understand the amazing biodiversity on the Earth. First, individuals are not identical among them, i.e., there exists variation in the traits among the members of a given population, species, etc. Second, phenotypic variation leads to differential survival and reproduction of the organisms that are best fitted to the environment (i.e., competence among the members of the population). Finally, phenotypic traits are passed from generation to generation (i.e., phenotypic variation is inheritable), thereby favoring offspring from parents more adapted to the environment.
