Question

Which one of the following is oviparous?
A. Platypus
B. Flying fox (bat)
C. Elephant
D. Whale

Answer 1

Hint: Sexual reproduction can be defined as the reproduction of an organism with two sets of chromosomes by the fusion of gametes which consist of a single set of chromosomes. Many plants, animals, and fungi reproduce sexually. Depending upon the type of sexual reproduction animals are classified as oviparous animals or viviparous animals.

Complete answer: Oviparous animals are those animals who lay their eggs and no embryonic development is seen within the mother. Most of the fishes, reptiles, birds, and amphibian's mode of reproduction are oviparity. In oviparity the fertilization is internal. The females lay their eggs which contain zygote. A substantial quantity of yolk is present in the zygote while it remains in the egg to feed the embryo. During the period of development of the embryo within the egg, the egg is not present in the body. This is the main difference between oviparity and viviparity. Most of the Arthropoda are oviparous. The mode of reproduction of platypus which belongs to monotremes is oviparity. The development of the embryo inside the body of the parent is called viviparity. Viviparous animals develop their young ones inside their body. The development of embryos takes place in specialized organs that supply nutrients to the developing embryo. Among the options provided, the only platypus is an oviparous animal.
So, option A is the correct answer.

Note: Matrotrophy is a condition in which the young one receives nutrition directly from the mother and not from the yolk. The yolk sac still plays a role in some primitive viviparous animals. The ability to reproduce at any time of the year is the benefit of viviparity.