Question

In these animals, the female retains the eggs inside the body after fertilisation and allows the development of embryos inside the body without providing extra nourishment to the developing embryo as the placenta is absent. Such animals are called as
(a) Oviparous animals
(b) Viviparous animals
(c) Ovoviviparous animals
(d) None of the above

Answer 1

In the animal kingdom, some animals lay eggs while some give birth to live young ones. Accordingly, they can be named as Oviparous or Viviparous. But some organisms develop eggs and retain them within the body and later hatch them inside the bodies to give birth to live young ones. Some examples of such animals are sharks and rattlesnakes.

Complete Step by Step Answer:
The animals that lay eggs are known as Oviparous animals, while those that give birth to live young ones are called Viviparous animals. However, animals like sharks that develop eggs but retain them within the body and later hatch them within their bodies to give birth to live young ones are a hybrid of both these phenomena. Such types of animals are known as Ovoviviparous animals.
They do not provide any extra nourishment to the embryo as in the case of viviparous animals, as they do not possess a placenta. However, the egg pouch in which the embryo develops has all the necessary nutrition for the embryo to develop.
They adopt this method to ensure that the eggs are safe and thus ensure better chances of survival for the young ones.
So, the correct answer is, ‘(c) Ovoviviparous animals.’

Note:
- In most cases, the mother does not provide any nutrition as the placenta is absent and the yolk sac is the mode of nutrition for the embryo. However, the mother’s body does help in gaseous exchange.
- In some ovoviviparous animals, the embryo exhausts the yolk in early gestation, and in such cases, the mother does provide extra nutrition. It may be in the form of unfertilized eggs or sometimes through uterine sections.