X and Y are the two types of animals. The animals like X undergo external fertilization whereas animals like Y undergo internal fertilization. The animals like X lay eggs from which baby animals are hatched. On the other hand, in animals like Y, the young one develops inside the uterus of mother which then gives birth to the baby.
(a) What is the general name of animals like X ?
(b) Give two examples of animals like X ?
(c) What is the general name of animals like Y ?
(d) Write the names if two animals like Y.