Question

Heart of fishes is:
A. Two chambered
B. Venous heart
C. Both of the above
D. None of the above

Answer 1

Hint: A muscular chambered heart is present in all the vertebrates from human to fishes. A 2- Chambered heart is a heart which only possesses two chambers i.e a ventricle and an atrium. A heart in which the deoxygenated blood is received through the veins is considered to be a venous heart.

Complete answer:
Unlike humans, a 2-chambered heart is found in the fishes in which only a single ventricle, as well as an atrium, is present. As in humans, double circulation occurs in the heart. Similarly, fish have a 2-chambered heart, so a single circulation occurs.
Deoxygenated blood is pumped out in fishes which is turned into oxygenated blood by the gills. This oxygenated blood is transported to all the body parts of the fish for performing many bodily functions. The deoxygenated blood (Blood after being used by various body parts becomes deoxygenated) is returned to the heart and this process is known as single circulation.
In fishes, the deoxygenated blood which is pumped by the heart is received by the veins of the heart. This blood is then sent by the veins to the gills of the fish for the blood's oxygenation. Therefore, the hearts of the fishes are also considered to be a venous heart.

Hence, the correct option is (C) Both of the above.

Note:
The students might get confused between the function of the atrium and the ventricle. Atria is referred to as receiving chambers whereas ventricles are referred to as pumping chambers. Atria is typically the first stop from where the blood enters the heart while the blood is pushed out of the heart from the chamber named ventricle.