| A | B |
|---|
| endoskeleton | primary support inside the body |
| skull | covers and protects brain |
| cartilage | support tissue more flexible than bone |
| heart chambers | spaces in the heart |
| central nervous system | brain and spinal cord |
| peripheral nervous system | nerves and sensory receptors |
| fish | aquatic animals with gills and fins |
| amphibians | live in water as young, may live on land as adults |
| reptiles | live on land with dry, scaly skin |
| kidney | organ used to filter blood |
| liver | secretes bile for digestion |
| gallbladder | stores bile |
