According to one hypothesis, the jaws of vertebrates were derived by the modification of
A)scales of the lower lip.
B)skeletal rods that had supported pharyngeal (gill)slits.
C)one or more gill slits.
D)one or more of the bones of the cranium.
E)one or more of the vertebrae.

Question

Quizplus · Accepted Answer

The hypothesis holds that vertebrate jaws evolved from skeletal rods that supported gill slits in early chordates. The gill slits were eventually modified into jaw structures, leading to the evolution of the wide diversity of jaw types seen in modern vertebrates.

According to One Hypothesis, the Jaws of Vertebrates Were Derived