What are mammals?

• A. Cold-blooded vertebrates that lay eggs
• B. Animals that have feathers and can fly
• C. Vertebrates that get milk from their mothers and have fur
• D. Animals without backbones that live in water

Answer: (C)

Mammals are defined as vertebrates that possess certain key characteristics, including the ability to nurse their young with milk produced by mammals, usually through mammary glands. This is an essential feature that distinguishes them from other animal groups. Additionally, most mammals have fur or hair on their bodies, which helps with insulation and protection. This combination of traits, specifically the presence of mammary glands and fur, categorizes animals as mammals.

The other descriptions do not accurately define mammals. Cold-blooded vertebrates that lay eggs refer to reptiles or amphibians. Animals that have feathers and can fly are classified as birds. Lastly, animals without backbones that live in water describe various species of invertebrates, such as fish or mollusks. Thus, the defining characteristics of mammals are accurately represented in the correct choice, highlighting their unique position in the animal kingdom.