| A | B |
| neuron | basic unit of the nervous system |
| immune system | helps protect you from pathogens/made of blood cells and tissues |
| infectious disease | a disease that you can pass from one organism to another |
| voluntary muscles | muscles that you can control |
| involuntary muscles | muscles that you cannot control |
| pathogens | organisms that cause some diseases |
| vaccine | a kind of medicine that can help protect you from disease |
| circulatory system | heart is the main part of this |