Final answer:
Sexual reproduction significantly increases genetic variation by combining genetic material from two parents, contributing to species survival in a changing environment.
Step-by-step explanation:
Sexual reproduction helps to increase genetic variation. This occurs because sexual reproduction combines the genetic material of two individuals, resulting in offspring that are genetically unique. Genetic variation is critical for the survival of species, as it leads to diverse phenotypes that might have an advantage in a changing environment. The mechanisms of meiosis such as independent assortment and crossing-over, as well as the random fusion of gametes during fertilization, all contribute to this variation. Additionally, sexual reproduction allows for mutations to be reshuffled from one generation to the next, creating even more genetic diversity.