True brains and spinal cords occurred first in
A)chordates.
B) mollusca.
C)crustacean.
D)hemichordates.

Question

True brains and spinal cords occurred first in 
A)chordates. 
B) mollusca.​ 
C)crustacean. 
D)hemichordates.

Quizplus · Accepted Answer

True brains and spinal cords evolved first in chordates, which include vertebrates such as fish, amphibians, reptiles, birds, and mammals. Hemichordates are also considered to be evolutionary precursors to chordates, but they do not have true brains or spinal cords. Mollusca and crustaceans do not have true brains or spinal cords either.

True Brains and Spinal Cords Occurred First in