Answer:
1. Sexual Reproduction
2. Genetic variations
Step-by-step explanation:
Human reproduces through sexual reproduction. Sexual reproduction is the process of production of new progeny by the formation of male and female gametes (sperms and egg respectively) and fusion of gametes. During gamete formation, crossing over adds new gene combinations to the gametes. The genetic variations make the progeny of sexual reproduction different from each other and from the parents.