| Humans have 20 primary and 32 permanent ____. |
bacteria |
| Insulin and glucagon are ____ that regulate blood glucose. |
cartilage |
| Red blood cells, also known as ____, deliver oxygen. |
erythrocytes |
| Your spine (backbone) is made of 33 bones called ____. |
hormones |
| Biceps and triceps are upper arm ____. |
muscles |
| The structure of your ears and nose is made of ____. |
teeth |
| Botulism, cholera, plague, and tetanus are caused by ____. |
tissues |
| Human cells organize first into ____ and then into organs. |
vertebrae |
