Gas exchange

 Answers

1. Circulatory system takes  care with our breathing.
2. Our nose, mouths, windpipe, lungs, bronchi and trachea.
3. They diffuse oxygen into the blood and receive carbon dioxide.
4. Carbon dioxide travels out of your body when you exhale.
5. A large muscle under your lungs, pulls down. This gives plenty of room so you can get the air you need.