Introduction to Mammals: Features, Diversity, and Adaptations

Mammals are a diverse group of vertebrates belonging to the class Mammalia. They include some of the largest and most intelligent animals, such as whales and primates. Mammals first appeared around 225 million years ago and have evolved various traits, including nocturnal and diurnal behaviors. Unique features of mammals include sweat and mammary glands, a specific jaw joint, a middle ear, and teeth that are replaced once or not at all. Mammals are mostly viviparous, giving live birth, and are endothermic, allowing them to survive in cold climates.

How do the teeth of mammals differ from those of other animals?

Explain the term 'viviparous' in the context of mammals and provide examples.