During chordate evolution, what is the sequence (from earliest to most recent) in which the following structures arose?
1. amniotic egg
2. paired fins
3. jaws
4. swim bladder
5. four-chambered heart
A) 2, 3, 4, 1, 5
B) 3, 2, 4, 1, 5
C) 3, 2, 1, 4, 5
D) 2, 1, 4, 3, 5
E) 2, 4, 3, 1, 5
