A common characteristic of all vertebrates without exception is
A. the division of body into head, neck, trunk and tail.
B. body covered with exoskeleton.
C. the possession of two pairs of functional appendages.
D. the presence of well- developed skull.
Correct Answer : D.
The sub-phylum vertebrata (or craniata) have a welldeveloped nervous system that is differentiated into brain and spinal cord. Brain is protected by a brain box called cranium, so they are also called as craniata.