Which of these might have been observed in the common ancestor of chondrichthyans and osteichthyans?
A) a mineralized, bony skeleton
B) opercula
C) a spiral valve intestine
D) a swim bladder

Question

Quizplus · Accepted Answer

The common ancestor of chondrichthyans (cartilaginous fish) and osteichthyans (bony fish) likely had a mineralized, bony skeleton, as this is a primitive trait that was present before the divergence of these two groups.

Which of These Might Have Been Observed in the Common