Answer:
genetic variation
Step-by-step explanation:
Genetic variation can be defined as the difference in the genetic material of individuals in a given population. This variation in the genetic load of a population plays a fundamental role in the evolution of species, since natural selection acts by selecting the most advantageous genotypes in a given ecological condition and making those that are disadvantageous for this condition rare. Such variation in genetic material can occur when a central C-G base pair in the DNA molecule is replaced by an A-T base pair, for example.