Question

Why do animals that reproduce through internal fertilisation produce fewer eggs than those that reproduce through external fertilisation?

Answer 1

In external fertilisation, the gametes are released outside the body in water, which increases the chances of loss of the gametes. To increase the chances of fertilisation, gametes are produced in large numbers. But, in internal fertilisation, the eggs are protected in the female body, and thus fewer eggs are produced as the chances of fertilisation are high.