Question

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: Cephalochordates differ from cyclostomes and other vertebrates in most of their primitive features and the same raise objection for their affinity. Reason R: Branchiostoma possess all the important chordate characters. Choose the most appropriate answer from the options given below

• A. Both A and R are correct and R is the correct explanation of A.
• B. Both A and R are correct but R is NOT the correct explanation of A.
• C. A is correct but R is not correct.
• D. A is not correct but R is correct.

Hint:

Branchiostoma shows all basic chordate characters.

Answer 1

The Correct Option is D

Concept:
Cephalochordates are primitive chordates showing typical chordate features.
Step 1:
Cephalochordates actually show affinity with vertebrates through primitive chordate characters. Thus Assertion A is incorrect.
Step 2:
Branchiostoma possesses:
• Notochord
• Dorsal hollow nerve cord
• Gill slits Thus Reason R is correct.
Step 3:
Since Assertion A is false, explanation relation is invalid.
Step 4:
\[ \boxed{\text{A is not correct but R is correct}} \] \[ \boxed{\text{Correct Option = (4)}} \]