1. They have beaks and are covered with feathers. 2. They have gills used in breathing and fins for swimming. 3. They lay eggs on land such as snakes and gecko 4. They have mammary glands which produce milk for their young 5. They have moist and thin skin and live on land and in water. 6. Their bodies are covered with fur and hair. 7. They are cold-blooded animals such as mudfish and tilapia. 8. Their bodies are covered with dry scales. 9. They are warm-blooded animals, and most are adapted to flight. 10. They use gills to breathe while young and lungs when they become adults.