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

Hint: All four animals of this group belong to the class Mammalia and either they live on land or in water. They never lay eggs but give birth to the young ones only.

Complete answer:
Dolphin, Kangaroo, Bat, and Cat all of them give birth to their young ones. These were viviparous animals. Viviparous are those animals that give birth to live young one that have developed inside the body of the parent.
-Birds and mammals are animals adapted for the terrestrial mode of life. All birds lay eggs, whether they belong to the group of flight as well as non-flight or flightless birds, like Kiwi, Penguin, and Ostrich.
-Mammals are characterized by the presence of mammary glands and placenta. They produce young ones and nourish them through mammary glands e.g., kangaroo, hedgehog, lion, cat, bat, loris, etc. -Platypus is a primitive egg-laying mammal, dolphin and whale are the young ones producing or aquatic mammals.
-In the viviparous mammals the most important transition that occurs after the egg is fertilized leading to the pregnancy period and then birth. The uterus increases in size in proportionate to the growth of the zygote, during the pregnancy stage.
-It provides potential health risk and discomfort. During this period the female begins to experience a series of internal and external changes in preparation of the eventual birth and its aftercare needs.

So, the correct answer is, ’Dolphin, Kangaroo, Bat, Cat’.

Note: -Not all, developing fetuses of viviparous animals are connected to a placenta in the mother's body.
-The placenta is a membranous organ that contains a rich and powerful blood supply.
-The placenta envelops the uterus of pregnant females and it feeds the fetus with a nutritional supply line known as the umbilical cord.
-The time between fertilization and birth of viviparous animals is called the gestational or pregnancy period and it varies depending on each species.