Assertion : In fishes, heart is venous.
Reason : Only veins are present in the heart of fishes.

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

C

Explanation

In fishes, the heart is mainly two chambered one auricle and one ventricle. Heart of Scoliodon receives only deoxygenated or venous blood, hence named as venous heart. The auricle opens to the ventricle through atrioventricular aperture. Mainly the impure blood passes from the heart to the gills only once. Therefore, they have single circulation only.