Explanation

Syngamy (fertilisation) fusion of male and female gametes is called syngamy or fertilization. It is of two types (i) External Fertilisation When the syngamy takes place in the external medium. Generally, the external medium is water, $e.g.,$ Amphibians, fishes (ii) Internal Fertilisation When the syngamy takes place inside the female body, $e.g.,$ Reptiles, bird, mammals