Question

Why do animals undergoing external fertilization produce more egg cells than those undergoing internal fertilization?

Answer 1

Animals undergoing external fertilization lay hundreds of eggs and release millions of sperms, all the eggs do not get fertilized and develop into new individuals. This is because the eggs and the sperms get exposed to water movement, wind and rainfall. Also, there are other animals in the pond which may feed on eggs. Thus, production of large number of eggs and sperms is necessary to ensure fertilization of at least a few of them...