Hint: Duck Billed platypus is a kind of an aquatic mammal. It shows features like duck-like beak. It has padded feet that are used for swimming. It is termed as a mammal because it feeds its young ones by its milk. It shows many features like that of the mammals.
Duck-billed platypuses are small and these are shy species. They show the presence of flattened heads and body that make them float easily across the water. The colour of their fur is dark brown that is present on the top and tan on their bellies. These are dense and repel the water current to let them warm and dry even after hours of swimming. Their head and body grow to a size of 15 inches and tail grows to about 5 inches in length.
Now let us find solution from given options:
Lacks hair : Platypus is a well-known example of mammals as like all the mammals it also shows presence of hairs on its body.
Is cold blooded : Like other mammals it is a poikilothermic that maintains homeostasis and can not change their temperature.
Doesn’t secrete milk : Like other mammals they possess mammary glands so they help to secrete milk and eject milk.
Doesn’t give birth but lays eggs : All the other mammals are viviparous in nature, that is they directly produce young ones except for these Platypus they produce young ones and are oviparous in nature.
Hence, the correct answer is option (D)
Note: Platypuses are long-lived, and shows living in captivity for 20 years or more and in the wild for up to 12 years. Scientists claim that these mysterious animals are the first ancestors of modern mammals. These are only mammals that are oviparous in nature.