Question Detail
Question
Which of the following is NOT a characteristic shared by all mammals?
Correct Answer
Option D is the correct answer.
Detailed Explanation
While all mammals have a four-chambered heart, this feature is also shared with birds and some other vertebrates. The defining characteristics shared by all mammals are three middle ear bones (ossicles), hair, and mammary glands.
Hint
Identify which feature is not unique to mammals or is absent in some mammals.