Final answer:
Genetic variations are predominantly the result of mutation and sexual reproduction, which introduce new genetic diversity crucial for a species' adaptability and evolution.
Step-by-step explanation:
Genetic variations within a species are most frequently the result of mutation and sexual reproduction. Mutations are permanent changes in the DNA that produce new genetic variations, which may lead to different traits among individuals in a population. Sexual reproduction also contributes to genetic diversity by combining the genetic material from two parents, resulting in offspring with unique genetic combinations. Environmental factors and gene flow, where alleles move in and out of a population, play roles as well but do not directly create new genetic variation.
Natural selection, genetic drift, and gene flow also influence genetic variance within a population. Natural selection favors individuals with beneficial traits that improve survival, while genetic drift involves random changes in allele frequencies. Lastly, genetic diversity provides a species with greater evolutionary potential, ensuring adaptability and survival in changing environments, illustrating its critical role in the long-term preservation of species.