Question

Why eggs laid by a frog are many in number whereas a hen lays only one egg

at a time?​

Answer 1

Answer:

Explanation:

Fishes and frogs lay hundreds of eggs as compared to the hens because :

(1) External fertilization is occurring in fishes and frogs.

(2) The male releases a large number of gametes in the external medium (Water) while the female parent lays a vast number of eggs.

(3) Eggs and sperms may be carried to large distances or may be consumed by predators present in the medium thus loss of the gametes can take place.

(4) Hence in fishes and frogs, the fertilization of male and female gamete is a chance factor and it depends on nature too.  

So, to increase the chances of fertilization a large number of gametes are produced in these organisms.

While, on the other hand, egg development in the hen takes inside uterus thus loss of gamete does not take place therefore in hen the zygote formation is not controlled by nature.