| Your trachea divides into two main ____ that lead to your lungs. |
antibiotics |
| Your two ____ take in oxygen and expel carbon dioxide. |
atria (atriums) |
| Blood travels from your legs to your heart through ____. |
bronchi |
| Human cells organize into ____ and then into organs. |
lungs |
| The ____ are the two upper chambers of the heart. |
muscles |
| Biceps and triceps are upper arm ____. |
pathogens |
| Bacteria or viruses that cause diseases are called ____. |
tissues |
| The reproduction of bacteria can be stopped by ____. |
veins |
