C
in the first paragraph a fact is challenged
and the second one provides an example
D. They both help organisms to move.
The genetic variation of organisms has three sources they are mutation, gene flow and sexual reproduction.
Explanation:
Genetic variation are caused by mutation , random mating, random fertilization and recombination between homologous chromosomes during meiosis.
It is a variation in alleles and genes, among the populations. There is a genetic variation within the family of closely- related individuals. If it is a neighborhood there are many families and there is also genetic variation among that group.
An exact genetic copy of the parent organism is produced in asexual reproduction. It only introduces the genetic variation into the population if a random mutation in the organism's DNA is passed on to the offspring.
