The right option is; B. A walrus stays warm in the cold ocean.
"A walrus stays warm in the cold ocean" is the result of an organism having lipids in its body.
Walrus have a thick layer of lipids or fat (adipose tissue) known as blubber under its skin which functions as a barrier and reduce heat loss from the body as a result of the extreme outer colder environment. Lipids prevent marine mammals from getting too cold and help them to stay warm in cold environment.
The acetabulum is the cup-like structure where the femur articulates. The head of the femur is the specific structure which articulates in the acetabulum.
