Answer:
The correct answer would be A) Variation is aided by crossing-over which occurs during meiosis.
Meiosis increases the genetic variation of the population which increases the survival rates of the population in the changing environment.
Meiosis helps in achieving genetic variation in two ways:
- Crossing over during which non-sister chromatids of homologous chromosomes exchange their genetic material. It occurs in the pachytene stage of prophase I during the process of synapsis.
- In addition, the zygote is formed by the fusion of two gametes which also leads to the production of a unique combination of genes in an organism.