$$ extbf{Solution:}$$ $$ullet$$Sexual reproduction is the fusion of the male and female gametes either produced by a single organism (in the case of bisexual flowers) or by two different organisms (in the case of humans). $$ullet$$Sexual reproduction leads to the development of the new variation of characters in the offspring due to the mixing of the chromosomes from the two organisms and hence it allows the improvement of progeny. $$ullet$$Variation leads to evolution and hence higher organisms restore sexual reproduction in spite of their complexity.