CBSE Class 10 Answered

Fishes show single circulation whereas humans show double circulation. This means that in fishes, blood goes only once through the heart during one cycle of passage through the body. In humans, blood flows twice through the heart, during each cycle of passage through the body.

Fishes have only 2 chambers in their hearts, whereas humans show 4 chambers.

In fishes, blood is pumped from heart to gills, where it is oxygenated. After oxygenation, it passes directly to the rest of the body. In humans, blood is pumped from heart to lungs for oxygenation. But after oxygenation, the blood is again taken to the left side of the heart from where it is pumped to the rest of the body.