What are the characteristics of reptiles?

The characteristics of reptiles are:

1. They are cold-blooded animals.
2. They have dry skin covered with horny epidermal scales.
3. Respiration takes place through lungs.
4. Their heart is three-chambered except crocodiles that have a four-chambered heart.
5. They lay eggs that have leathery waterproof shells.
6. Most of them spend their life on land. They have two pairs of legs.