Higher plants (angiosperms) and higher animals (vertebrates) have a more complex structural organisation as compared to the lower groups of plants and animals. They have evolved very efficient mechanism of sexual reproduction. These groups have resorted to reproduction by the sexual method for the following reasons.
(i) To ensure healthy progeny
(ii) To produce genetically varied offsprings that adapt to changes in environment and surviveal in all climatic conditions.
(iii) It ensures the genetic recombination that results in variation which gives rise to evolution.
