What characterizes reptiles?

• A. Warm-blooded vertebrates
• B. Scaly or plated vertebrates
• C. Soft-bodied invertebrates
• D. Aquatic mammals

Answer: (B)

Reptiles are characterized by their scaly or plated skin, which helps to prevent water loss and provides protection. This unique feature allows them to adapt effectively to various environments, particularly those that are dry or hot. The scales are made of keratin, the same material that makes up human nails and hair, contributing to their ability to thrive in their habitats. Reptiles are also cold-blooded vertebrates, meaning their body temperature is regulated by the temperature of their environment, but "scaly or plated vertebrates" is the defining characteristic that clearly identifies them within the animal kingdom. Recognizing this trait is essential for understanding how reptiles differ from other animal groups, such as mammals and amphibians.