Question

Why do fish and frogs lay eggs in hundreds whereas a hen lays only one egg at a time? [3 MARKS]

Answer 1

Each point: 1.5 Mark
1. Many aquatic animals lay hundreds of eggs and release millions of sperm, all the eggs do not get fertilized and develop into new individuals. This is because the eggs and sperm get exposed to water movement, wind, and rainfall.
2. Also, other animals in the pond may feed on eggs. Thus, the production of a large number of eggs and sperm is necessary to ensure the fertilization of at least a few of them.

3. In hens, fertilization is internal with much higher chances as compared to most aquatic animals with external fertilization with fewer chances as gametes are outside the body.