| A | B |
|---|
| cartilage | tough, flexible tissue not bone |
| chordate | animal that has a notochord |
| ectotherm | vertebrate animal whose internal temperature changes |
| endoskeleton | supportive framework of bone and/or cartilage |
| endotherm | vertebrate animal with constant internal temp |
| nocturnal | inactivity in the daytime |
| hibernation | inactivity in cold weather; |
| nerve cord | tubelike structure above the notochord |
| notochord | firm, flexible structure that extends along the upper part |
| pharyngeal or gill pouches | paired openings found in the area between mouth and digestive tube |
| upper fin | fin that keeps fish upright in the water |
| vertebrae | backbones that are joined by flexible cartilage and protect a vertebrate's spinal nerve cord |
