Assertion : Respiration in Amphioxus is done by both water and blood.
Reason : Amphioxus is aquatic and possesses blood

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

A

Explanation

In Amphioxus, some exchange of `O_2` and `CO_2` occurs between the water current and blood through the gill- clefts, but this appears doubtful since the blood contains no respiratory pigment. The pharyngeal wall of Branchiostoma is richly vascular and the water current entering the pharyngeal cavity brings . `O_2` The blood flows so close to the surface that some exchange between `CO_2` of blood and `O_2` of water can easily occur.