What is a defining feature of mammals that is not present in most other OA.
OB.
C
D
Mammals maintain a constant body temperature.
Mammals can produce milk for their offspring.
Mammals have a nervous system with a spinal cord.
Mammals reproduce through internal fertilization.
O

Explanation:

Mammary glands are evolved from the modification of sweat glands. Mammary glands produce milk for their offspring. presence of hair on the body is also a defining feature of mammals. These defining features are not present in most of the vertebrates.

Hope this helps

b brown mice / white sand dunes