| A | B |
|---|
| Bone marrow | Produces the cells that are in your blood. |
| Skeletal muscles | Bones to help you move. These are voluntary muscles. |
| Smooth muscles | Control the movements necessary for your body's internal organs and blood vessels to function. Controlled by the brain, so movements they cause are involuntary. |
| Cardiac muscle | A muscle found only in the heart. It controls how the bolld is pumped throughout your body. |
| Keratinization | The process of skin cells hardening so that they form your hair, nails, and the outer layer of your skin. |
| Endoskeleton | The sum total of all bones in the body. |
| Vertebrates | All creatures with a vertebral column backbone. |
| Axial skeleton | The portion of the skeleton that supports and protects the head, neck, and trunk. |
| Appendicular skeleton | The portion of the skeleton that attaches to the asial skeleton and has the limbs attached to it. |
| Invertebrates | Organisms from kingdom Animalia with no backbone. |
| Exoskeleton | A body covering, typically made of chitin, that provides support and protection. |
| Arthropods | Animals with exoskeletons, such as grasshoppers. |
| Tendon | Connective tissue that attaches the skeletal muscles to the skeleton. |
| Cartilage | A tough flexible substance that allows joints to rub up against each other without damage. |
| Ligament | Tissue that hold together two bones that are jointed. |
| Synovial fluid | Lubricates the joints so that their motion is smooth and easy. |
| Involuntary muscles | Muscles that cause involuntary movement, which is movemement made without conscious thought |
| Phototropism | The tendency of plants to grow so that they face the light. |
| Gravotropism | The tendency for a plant to sense which way is "up" and to grow that way. |
| Epidermis | Outer layer of skin. |
| Dermis | The inner layer below the epidermis. |
| Hypodermis | Below the dermis and composed mostly of fat. It is not technically considered part of the skin. |
| Symbiosis | A close relationship between two or more species where at least one benefits. |
