Question

Identify the group, which includes animals all of which give birth to young ones directly?
A. Dolphin, kangaroo, bat, cat
B. Platypus, penguin, bat, hippopotamus
C. Shrew, bat, kiwi, cat
D. Lion, whale, ostrich, bat

Answer 1

Animals that give birth to their young ones directly are kept under the class Mammalia. These animals nourish their young ones. Mammals are a class of phylum Chordata or Vertebrata that consists of animals with a notochord that develops into a vertebral column.

Complete answer: Mammals belong to the superclass Tetrapoda. Tetrapoda consists of animals with four limbs. These animals have mammary glands to feed and nourish their young ones. Examples; dolphin, kangaroos, bats and cats. All these given animals are mammals. Dolphins belong to the order Cetacea of mammals. Kangaroo belongs to the subclass Marsupia of mammals. Bat belongs to the order Chiroptera of mammals. The cat belongs to the order Carnivora of mammals. All these animals give birth to their young ones directly and nourish them with their milk.
a) Platypus, penguin, bat, hippopotamus – All these given animals are mammals except for penguins. Platypus belongs to the subclass Prototheria of mammals. These animals do not give birth to their young ones directly but instead, they lay eggs. However, they nourish their young ones with their own milk. Penguin belongs to the class Aves. Members of Aves lay eggs. Bat belongs to the order Chiroptera of mammals. Hippopotamus belongs to the order Artiodactyl of mammals. Bat and hippopotamus give birth to their young ones directly and nourish them with their milk.
b) Shrew, bat, kiwi, cat – All these given animals are mammals except kiwi. Shrew belongs to the order Eulipotyphyla of mammals. Bat belongs to the order Chiroptera of mammals. Kiwi belongs to the class Aves. Members of Aves lay eggs. The cat belongs to the order Carnivora of mammals. Shrew, bat, and cat give birth to their young ones directly and nourish them with their milk.
c) Lion, whale, ostrich, bat – All these given animals are mammals except for the ostrich. Lions belong to the order Carnivora of mammals. Whales belong to the order Cetacea of mammals. Ostrich belongs to the class Aves. Members of Aves lay eggs. Bat belongs to the order Chiroptera of mammals. Lions, whales, and bats give birth to their young ones directly and nourish them with their milk. Thus, based on the above information, we can conclude that the group dolphin, kangaroo, bat, cat, etc. includes animals all of which give birth to young ones directly.
Hence, the correct answer is option A.

Note: Prototheria is also known as Monotremata. This subclass consists of egg-laying mammals. These animals have a cloaca. They also have a T-shaped clavicle. These animals lay the cleidoic eggs. They have mammary glands without the top part. They are considered a connecting link between reptiles and mammals. These animals also show gynandromorphism.