Question

In which one of the following sets of animals does all the four-give birth to young ones?
A. Shrew, Bat, Cat, Kiwi
B. Kangaroo, Hedgehog, Dolphin, Loris
C. Lion, Bat, Whale, Ostrich
D. Platypus, Penguin, Bat, Hippopotamus

Answer 1

Hint: There are two types of animals- oviparous and viviparous.The viviparous are young ones laying animals. Viviparity is the development of an embryo inside the body of the parent and finally giving birth to them. Most mammals are viviparous.

Complete answer: Animals such as birds and mammals are adapted to survive in the terrestrial mode of life. Birds are oviparous i.e. they lay eggs. Flight, as well as non-flight birds such as kiwi, penguin, and ostrich, lay eggs. Mammals are characterized by the presence of mammary glands and placenta and most of them are viviparous. They produce young ones and nourish them by the mammary glands. Mammals such as kangaroo, lion, hedgehog, bat, cat, loris, etc. Platypus is a primitive semi-aquatic egg-laying mammal whereas dolphins and whales are viviparous aquatic mammals.
Hence, the correct option is (B), i.e., Kangaroo, Hedgehog, Dolphin, Loris.

Note: Viviparous animals give birth to young ones and the embryos are raised with special organs in the parents. The mother feeds the young ones with nutrients from their mammary glands. Most of the viviparous mammals are domesticated by humans. Viviparous mammals can show internal or external fertilization. After internal fertilization, the development of embryos takes place inside the maternal body. Whereas when animals lay fertilized or unfertilized eggs, they are considered oviparous mammals.