Mention briefly about the circulatory system of earthworm.

Explanation

The circulatory system of earthworm is of closed type consisting of blood vessels, capillaries and heart. Blood is red, haemoglobin is dissolved in blood plasma. Blood glands are present on the 4th , 5th and 6th segments. They produce blood cells and haemoglobin which is dissolved in blood plasma. Blood cells are phagocytic in nature. Due to closed circulatory system the blood circulates only into, blood capillaries, blood vessels and hearts. Due to contraction, blood circulates only in one direction. Smaller blood vessels supply the gut, nerve cord and the body wall.

Respiretory system : Earthworms lack specialised breathing devices. Respiratory exchange occurs through body surface into their blood stream. For this the body walls needs to be wet. Blood flow mixes in `O_(2)` from there.