Ques. 1AIPMT 2000
Which of the following characters is absent in all chordates?
- Diaphragm
- Coelom
- Pharyngeal gill clefts
- Dorsal nerve cord
Answer
(1) Diaphragm
Solution
The question asks which character is not common to all chordates.
As per NCERT, all chordates possess a notochord, a dorsal hollow nerve cord and paired pharyngeal gill slits; they are also coelomate.
⇒ A muscular diaphragm is present only in mammals.
∴ Diaphragm is the character not found in all chordates.
Answer: (1)