Internal and external fertilisation?

Internal fertilization-
In this type of fertilization, the fusion of the male and female gametes takes place inside the female's body, as in case of birds, mammals and reptiles.

External fertilization-
In this type of fertilization, the fusion of the male and female gametes takes place outside the body of the female, as in case of fish,frogs and star fish.

The gens present in the dna in the nucleus of the cell in the body

A. mitochondrion b. nucleus