| A | B |
|---|
| Cell | The basic unit of life in living things. |
| Microscopic | Too small to be seen without using a microscope. |
| Organism | Any living thing that maintains vital life processes. |
| Cell Membrane | The thin covering that surrounds every cell. |
| Nucleus | The part of the cell that directs all the cell's activities. |
| Cytoplasm | The jellylike material inside the cell. |
| Protist | A simple, single celled organism with a nucleus and organelles. |
| Tissue | A group of cells that work together to perform a certain function. |
| Organ System | A group of organs that work together to do a job for the body. |
| Organ | A group of tissues that work together to perform a certain function. |
| Digestive System | The organ system that turns food into nutrients that body cells need for energy, growth, and repair. |
| Circulatory System | The organ system made up of the heart, blood vessels, and blood that helps transport materials throughout the body. |
| Respiratory System | The organ system, including the lungs, that exchanges oxygen and carbon dioxide between the body and the environment. |
| Skeletal System | The organ system, including the bones, that protects the body and gives it structure. |
| Muscular System | The organ system that includes the muscles and allows the body to move. |
| Nervous System | The organ system including the brain, spinal cord, and nerves that senses your surroundings and controls other organs. |
| Excretory System | The organ system, including the kidneys and bladder, that removes waste materials from the blood. |
| Vacuole | The part of the cell where water, food, and waste are stored. |
| Mitochondria | The powerhouse of the cell, where energy is made from food. |
