| A | B |
|---|
| cells | group together to form tissues |
| tissues | group together to form organs |
| organs | group together to form systems |
| systems | work together to form organism |
| nerve cell | has fine extensions |
| white blood cell | can change its shape |
| red blood cell | disk-shaped, small, flexible |
| muscle cell | allow for contraction |
| sperm cell | has a flagellum for locomotion |
| unicellular organism | has only one cell |
| multicellular organism | has many cells |
| respiration | oxygen in; carbon dioxide out |
| waste removal | process to remove waste |
| growth | process of getting larger |
| irritability | ability to respond to environment |
| reproduction | process of producing offspring |
| cellular transport | moving materials in & out of cell |
| osmosis | water through a membrane |
| diffusion | high concentration to low |
| active transport | requires energy |
| passive transport | does not require energy |
