Question

The most important mammalian character of a rat is
A. Hair
B. Pinna
C. Diaphragm
D. Mammary glands

Answer 1

Rats are animals that belong to the phylum Chordata of class Mammalia. They are also called rodents and are commonly known as rats.

Complete answer: Kingdom Animalia is one of the three kingdoms and it is further divided into different classes. They are Vermes, Insecta, Amphibia, Aves and Mammals. Groups of animals that are characterized by the presence of mammary glands in females are placed in the Mammalia group. This characteristic of mammals makes them different from birds and reptiles. The four main characteristics exhibited by mammals are hair, diaphragm, mammary glands and three specialized middle ear bones. Out of these, the mammary gland is the most unique characteristic exhibited by only mammals and is not shared by any other group of animals. Rats belong to the genus Rattus. Rats are medium-sized which consists of a long tail. Rats generally possess a pointed head, large eyes, and prominent, thinly furred ears. They have long legs and long, sharp claws. Depending on the species, variable size of fleshy pads is present on the bald soles of their narrow hind feet. Rat is a mammal and exhibits the presence of mammary glands. Mammary glands present in the mammals are used to feed their young one with milk. Therefore, option D is the correct answer.

Note: Mammary glands are exocrine glands that are modified sweat glands in mammals that are able to produce milk in order to feed their young ones. The mammary gland is lined with milk-secreting cuboidal cells that secrete milk. In humans, females have mammary glands which secrete milk due to the action of the hormone prolactin.