Assertion : Characters of cyclostomes show an advance over Amphioxus.
Reason : Cyclostomes have some degenerated characters.

Options

A. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
B. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
C. If the assertion is true but the reason is false
D. If both the assertion and reason are false

Answer

B

Explanation

Following are the characiers of cyclostomes showing an advance over Amphioxus. A distinct head, however may be secondary, a so-called cranium, a more advanced brain, pro and mesonephric kidneys, secondary notochord, vertebrae introduced (lampreys) etc. Cyclostomes also have some particular specialization like tongue apparatus, sucking mouth with hrny teeth, sac-like gill pouches, separate branchial basket etc.
(i) tongue apparatus (ii) rudimentary paired eyes in hagfishes (iii) lack of exoskelecton (iv) reduced liver and lack of gall bladder and bile duct in adult lamprey.