Question

Type of fertilization (external or internal) depends on

• A. Structure of egg
• B. Site of embryo development
• C. Type of sperm
• D. Both A and B

Answer 1

The correct option is D Both A and B

Aquatic animals like fishes and amphibia usually show external fertilisation, whereas terrestrial animals like reptiles, birds and mammals show internal fertilisation. Egg of animal showing external fertilization is not covered by a hard, protective shell and after fertilisation the embryo develops into larva in water.

In terrestrial birds and reptiles the egg is covered with a hard, protective shell and development of embryo occurs inside egg. In mammals the egg is not covered by protective shell and fertilization is internal. After fertilization the zygote forms within the body of female animal and stays there till the formation of embryo.