Across
- 4. one of the flat pieces of hard material that covers the skin of a fish
- 5. this animal group has gills
- 7. to take air into and out of the lungs
- 8. the outer layer of a person or animals body
- 9. how big or small something is
- 12. to move smoothly over a surface
Down
- 1. the animal group that gives birth to live young, has fur or hair
- 2. one of the soft, light things that grow from a birds skin
- 3. a home built by birds for their eggs
- 5. to move through air
- 6. this animal group is cold blooded, they have scales
- 10. a part of the body that a bird uses to fly
- 11. to make it easier for someone to do something