The two different ways in which zygote develops following an internal fertilisation is:

1. By oviparity; where the fertilized zygote after being coated with protective layers, is laid out as an egg, and the further development of the zygote takes place outside the body of the mother.

Example: Hen.

2. By viviparity; where the fertilized zygote gets implanted in the maternal body, and the development takes place inside the mother’s body. In this, the mother gives birth to young ones.