Question

Select the incorrect statement.

• A. Jawless fishes have 6-15 pairs of gill slits.
• B. Reptiles have three-chambered heart except crocodile and cleidoic eggs
• C. Chordates have a solid dorsal nerve cord & notochord.
• D. Urochordata and Cephalochordata are often referred to as protochordates.

Answer 1

Answer: (C)

Animals belonging to phylum Chordata are fundamentally characterized by the presence of a notochord, a dorsal hollow nerve cord and paired pharyngeal gill slits. These are bilaterally symmetrical, triploblastic, coelomate with organ-system level of organization. They possess a post-anal tail and a closed circulatory system. All chordates possess this character at certain stage of their life cycle.