Question

fertilisation cannot be external in land animals .why?
please experts and friends answer fast its urgent

Answer 1

Fertilization can't be external in land animals because land provides a harsh and dry condition which is not suitable for the sperm and egg cells. As we know that sperm have tail to swim in watery condition.

Answer 2

Oviparous animals lay eggs outside their body. As a result, the eggs of these animals are under continuous threat from various environmental factors. On the other hand, in viviparous animals, the development of the egg takes place inside the body of the female. Hence, the offspring of an egg-laying or oviparous animal is at greater risk as compared to the offspring of a viviparous animal, which gives birth to its young ones.

Outside offspring or egg have many challenges to face...

And fission is not able to take outside..

For u I had taken it from else where hope it will help you n if then plz mark it as brainlist