In sexual selection, individuals with certain inherited characteristics are more likely to obtain mates than other individuals. this often results in differences between the sexes in size, appearance and behavior

Sexual dimorphism.

Explanation:

Sexual selection may be defined as the mode of natural selection in which the species choose its mate and prevent the other's individual mating. This provide better reproductive success in nature.

The sexual selection depends upon the attractive colors, size and behavior of other partner. The sexual selection results in sexual dimorphism as the male and female of the species can be easily distinguished. Their mating organ, behavior are different in opposite sexes.

Thus, the correct answer is sexual dimorphism.