Question

Which of the following is the distinguishing feature of all chordates?

• A. Presence of a ventral nerve cord
• B. Presence of a water-driven tube system
• C. Presence of a chitinous exoskeleton
• D. Presence of a notochord

Answer 1

The correct option is D Presence of a notochord

Chordates are animals possessing a notochord. The notochord, later on, gives rise to a bony vertebral column, which surrounds and protects the spinal cord.

All chordates have a dorsal nerve cord.

A water-driven tube system is a characteristic feature of echinoderms.

A chitinous exoskeleton is found in arthropods.

So, the correct answer is option D.