Question

Frogs and fishes lay hundreds of eggs at a time, however their population is very limited as compared to number of eggs they lay .Why?

Answer 1

Though fishes lay hundreds of eggs ,all the eggs do not get fertilised and develop into new individual.
This is because the eggs get exposed to water movement ,wind and rainfall.Also, there are other animals in the pond which may feed on eggs.Thus , the no.of eggs is necessary to ensure fertilisation of atleast a few of them.