Answer:
See explanation
Step-by-step explanation:
According to the theory of evolution,species which are better adapted to their environment tend to survive and reproduce in a population passing on these favourable characteristics to their offsprings.
During sexual reproduction, genes can be arranged in new ways from chromosomal crossing over and recombination. This introduces new gene combinations(genotype) and ultimately variation in the population.
This variation may also lead to the observation of new phenotypes in the population.