Question

what is external fertilisation and internal fertilisation.explain in brief.

Answer 1

fertilisation that takes place outside the body is called external fertilisation and fertilisation that takes place inside the body is called internal fertilisation

Answer 2

External fertilisation is fertilisation which occur outside the body.In external fertilisation,the female animal's eggs are fertilised by sperms outside the body.Example of external fertilisation are fishes and amphibians.
Internal fertilisation is a fertilisation which occur inside the female body.In the internal fertilisation,the female animal's eggs are fertilised by sperms inside the female body.Example of internal fertilisation are human being,birds and reptiles.