A swim bladder is a gas-filled sac that helps fish maintain buoyancy. The evolution of the swim bladder from the airbreathing organ (a simple lung) of an ancestral fish is an example of (A)...

buoyancy. The evolution of the swim bladder from the airbreathing

organ (a simple lung) of an ancestral fish is an

example of

(A) exaptation.

(B) changes in
Hox
gene expression.

(C) paedomorphosis.

(D) adaptive radiation.