The Chordates - Chapter 30 Assesment

1) c. 2) b 3) c 7) a
11) In most developing vertebrates, the notochord grows into the brain and hardens, turning into the spinal cord or backbone.
25) Two specialized structures that give amphibians movement are legs and fins. An example of legs would be a frog's hind legs that allow them to jump. An example of a fin would be the fins on a salamander that help them move through the water in an S-shaped pattern.
28) The world-wide decline of amphibian populations could be related to two of their prominent characteristics - Their skin is thin and must be kept moist and their eggs have no shell and must be kept moist. Global warming is reducing the amount of water that amphibians can use.