Animals

1. Birds

1.1. warm-blooded

1.2. skin covered with feathers

1.3. egg-laying

2. Amphibians

2.1. cold-blooded

2.2. water-breathing to air-breathing

3. Fishes

3.1. cold-blooded

3.2. skin covered with scales

3.3. 2 sets paired fins

4. Mammals

4.1. have hair on body

4.2. fed on mothers' milk

4.3. breathe with lungs

5. Reptiles

5.1. cold-blooded

5.2. skin covered with scales

5.3. egg-laying