| A | B |
|---|
| organ system | a group of organs that work together |
| cell | the basic unit of structure and function in a living thing |
| homeostasis | the body's tendency to keep an internal balance |
| epithelial tissue | tissue that covers the surface of your body |
| stress | the reaction of your body to potentially threatening events |
| nucleus | the control center of a cell |
| tissue | a group of similar cells |
| cell membrane | a cell structure that controls what can enter or leave the cell |
| cytoplasm | clear, jellylike substance within a cell |
| organ | structure composed of different kinds of tissue |
