Which one of the following is a mammal?
a) Hydrophis
b) Rhacophorus
c) Echeneis
d) Didelphis

Answer Verified Verified
Hint: The genus is from New World marsupials with a thick coat of fur, sharp claws, long whiskers, and a prehensile tail.

Complete answer: Didelphis as a mammal commonly known as large American opossums are members of the order Didelphimorphia. There are six species seen in the genus. The animals in this genus are noted by their prehensile tails and their tendency to feign death when cornered. They are cat-sized omnivorous species and are also known as opossums. There are different species of opossum, which are called possums in North America.
The only naturally occurring marsupial and the most notable one is Virginia opossum (Didelphis virginiana) or common opossum. It is the only marsupial found in the United States and Canada. It is also considered as the largest species in this genus. A female opossum gives birth to tiny babies as honeybees. Babies are helpless young ones who will immediately crawl into their mother's pouch, where they continue to develop. When they get larger, they will go in and out of the pouch and sometimes ride on the mother's back. Opossums may give birth to as many as 20 babies, but only half of them will survive.

So, the correct answer is Didelphis.

Note:Marsupials are the group of mammals which have pouches in their body, so they are pouched mammals like a kangaroo. They give birth, but they do not have long gestation times like normal mammals. They give birth at a very early stage and the young animal climbs from the mother's birth canal to the nipples. There it holds nipples with its mouth and continues to develop, for weeks or months depending on the species.