Across
- 1. system transports wastes and carbon dioxide throughout the body
- 5. pumps blood through the system
- 6. tiny openings in the side of their bodies
- 7. exchange gases with surroundings
Down
- 2. system gas exchange, taking in oxygen and removal of carbon dioxide
- 3. vertebrate animals respire using _______
- 4. blood circulates through the animals’ body inside these closed _______