Question

Assertion: Hemichordata was earlier considered as a subphylum under Chordata.
Reason: The stomochord of Hemichordates was considered similar to notochord of Chordates.

• A. Both assertion and reason are true and reason is not the correct explanation of assertion.
• B. Both assertion and reason are true and reason is the correct explanation of assertion.
• C. Assertion is true but the reason is false.
• D. Both assertion and reason are false.

Answer 1

The correct option is B Both assertion and reason are true and reason is the correct explanation of assertion.

Hemichordates are small worm-like marine animals which were earlier considered a subphylum of Chordata, based on the presence of gill slits; the dorsal nerve cord. However, a true notochord is absent. The buccal diverticulum or the stomochord resembles the notochord, so the reason for its earlier placement under Chordata.