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 gillclefts, but this appears doubtful since the blood contains no respiratory pigment. The pharyngeal wall of Branchiostoma is richly vascular cavity brings `O_(2)`. The blood flows so close to the surface that some exchange of gases occurs over the whole surface of the body and particularly in the walls of atrium.