Haritha,Subject Matter Expert at Edumarz
Solution:
Circulatory system of earthworm
The earthworm contains a closed type of blood vessel system. It is formed of blood vessels,capillaries, and the heart. Due to the presence of a closed type circulatory system,the blood of earthworms is restricted to the heart and the blood vessels.Contractions help to keep circulating blood flow to only one direction.Smaller blood vessels in the circulatory system supplies blood to the gut region,nerve cord, and body wall regions.The blood glands of the earthworm are located on the 4th, 5th, and 6th segments.These glands are responsible for producing blood cells and hemoglobin,and these cells are phagocytic in action.
Earthworm
Earthworms are reddish brown in colour.They live in the upper layer of moist soil.The common Indian species of earthworms are Pheretima and Lumbricus.The body of earthworms is cylindrical in shape.The body is divided into short segments called as metameres.The anterior region of earthworm contains mouth and the prostomium.The prostomium performs sensory functions.The first body segment of earthworm is known as peristomium.
Economic importance of earthworm
They are widely used in vermiculture to form highly fertile manure
Excreta of earthworm used in agriculture
They also increase aeration in soil