Question

Prototheria have developed from
(a)Birds
(b)Eutheria
(c)Amphibia
(d)Reptilia

Answer 1

Hint: Animals belonging to this class are cold-blooded, having dry and rough skin without any glands. The whole body of these animals is divided into head, neck, trunk, and tail.

Complete answer:
Prototheria has developed from Reptilia. They are referred to as monotremes which are classified as a subclass of mammals. In some aspects of their skeletons, prototheria is similar to reptiles. It is noticeable that their legs are on the sides of their bodies and not underneath them. This results in a reptile-like appearance.

Additional Information: - Prototheria, Metatheria, and Eutheria are the three mammalian groupings, which have living representatives that are animals of these classes who are still living on earth.
-Mammals give birth to their mature young ones directly in Eutheria. e.g, humans, and dogs.
-Mammals give birth to their immature young ones in Metatheria. So, till maturity, they stay into their mother's pouch.
-In Prototheria, mammals are egg-laying. e.g, Platypus, and echidna. Similarly, birds, amphibians, and reptilians also lay eggs. But unlike Prototheria birds have a pair of legs underneath them. Unlike Prototheria, amphibians do not have a tail-like structure.

So, the correct answer is "Reptiles"

Note:
 - From the fossils of the Cretaceous and Cenozoic periods the egg- laying monotremes are known. Today they are represented by the platypus and several species of echidna.
-Adelobasileus Crompton is the oldest mammal known from the Late Triassic of Texas. The marsupials and eutherians are known to arise during the Cretaceous period.