Question

Unique feature of the mammalian body is the presence of

Answer 1

Hint: Mammal, (class Mammalia), any member of the group of vertebrate animals whose young are fed milk from the mother's special mammary glands. All mammals' mature red blood cells (erythrocytes) lack a nucleus, whereas all other vertebrates have nucleated red blood cells.

Complete answer:
The unique feature of mammals is the presence of a diaphragm. It is the membrane that separates the thoracic cavity from the abdominal cavity. The diaphragm is a thin skeletal muscle that separates the abdomen from the chest and sits at the base of the chest. When you inhale, it contracts and flattens. This produces a vacuum effect, which draws air into the lungs. When you exhale, your diaphragm relaxes and the air is forced out of your lungs.

Homeothermy is thermoregulation which maintains a stable internal body temperature regardless of external factors. Homeotherms are the ones that can survive only within a range of temperatures like mammals, birds, and amphibians. So, Homeothermy is the property or characteristic which can be exhibited by a wide range of animals and not only humans.

The presence of four-chambered hearts are exhibited by aves and mammals, so it cannot be the unique feature of mammals.

The presence of rib-cage appeared first in reptiles, it is an attachment of ribs to a breastbone (sternum) to form a rib cage. It is a skeletal structure that forms the chest, thorax made of ribs and their corresponding attachments to the sternum and vertebral column.

Therfore the unique feature of mammals is ‘Diaphragm’.

Note: The diaphragm also has some nonrespiratory functions. The diaphragm raises abdominal pressure to assist the body in eliminating vomit, urine, and feces. It also puts pressure on the esophagus to keep acid reflux at bay.