List three distinguishing features between sexual and asexual types of reproduction. Explain why variations are observed in the offspring of sexually reproducing organisms?

a) In asexual reproduction, single parents produce offspring. Offspring are exact copies of their parents. In asexual reproduction, the fusion of gametes does not take place. In sexual reproduction, there is involvement of two parents. This method causes mixing of characters and hence offspring are not like their parents. In this method, the fusion of male and female gametes takes place.
b) In sexual reproduction, there is a fusion of male and female gametes which causes mixing of parent characters and thus, variation is observed in the offspring of sexually reproducing organisms.