Why do fish and frog produce more number of eggs

The type of fertilization in fish and frog is external fertilization i.e fertilization takes place outside the body. So the fish and frog produce a huge number of eggs each year to overcome the chance factor(sperm to come in contact with egg) and produce offsprings.

Explanation:

because the light is a great source of energy for the plants to survive. (i hope this )

the unequal cytoplasmic division that  results  in  one egg  and three polar bodies ensures that a fertilized  egg has  ample nutrients  forits journey  to  the uterus.