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 characters 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 horny teeth, sac-like gill pouches, separate branchial sac with branchial basket etc.
The degenerated characters of cyclostomes are –
(i) tongue apparatus (ii) rudimentary paired eyes in hagfishes (iii) lack of exoskeleton (iv) reduced liver and lack of gall bladder and bile duct in adult lamprey.