Question

Choose the correct answer from the alternatives given.
In which of the following animals is the blood entering the aorta incompletely oxygenated?

• A. Frog
• B. Pigeon
• C. Monkey
• D. Fish

Answer 1

The correct option is D Fish

In fishes, the oxygenated blood from the gills does not enter the heart. A heart does not receive oxygenated blood, so known as venous heart. It is directly distributed in the entire body. Only the deoxygenated blood enters the auricle and then the ventricle. The deoxygenated blood enters the gills for oxygenation from the ventricle. Blood has a slow flow and low pressure.

Monkey, pigeon, and frog have double circulation.

So, the correct option is 'Fish'.