Question

why frog lay hundred of egg as hen lay one

Answer 1

this is because frog eggs have no protective coating on them so survival rates are less therefore they are laid in abudance but on other hand hen's eggs have a protective coating of calcium so thier survival chances are more therefore laid in 1eggs.

Answer 2

In frog fertilization of eggs take place outside, because the eggs and sperms get exposed to water movement, wind ,rainfall and other marine organisms can harm them,so to ensure that a few out of many eggs laid may develop into tadpoles and frog, it is natural that frog lay hundreds of eggs. On the other hand, hen lays only one egg as it is completely protected and hence fertilization will take place.