The fluid part of the blood is called plasma. It is yellow in colour.

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$\begin{array}{ccc}\text{Sr.No.}& \text{Arteries}& \text{Veins}\\ 1& \text{They have thick}& \text{They have thin and}\\ & \text{elastic}& \text{less muscular walls.}\\ & \text{walls.}& \\ 2& \text{Direction of blood}& \text{Direction of blood flow}\\ & \text{flow is from the heart to}& \text{is from the organs of the body}\\ & \text{the organs of the body.}& \text{to the heart.}\\ 3& \text{They carry}& \text{They carry}\\ & \text{oxygenated blood}& \text{deoxygenated blood}\\ & \text{except in case of}& \text{except in case of}\\ & \text{pulmonary artery.}& \text{pulmonary vein.}\end{array}$

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Kidney is the organ responsible for purification of blood. The major excretory product in humans is urea. Urea, excess water and other waste products are filtered from the blood by kidneys. Kidneys produce urine which has all these wastes and is thrown out while urination.

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Xylem is one of the two types of vascular tissues in plants, phloem being the other. The function of xylem is to transport water and nutrients from the roots to all parts of the body.

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Blood is a liquid which has cells of various kinds suspended in it. The major types of cells in the blood include - red blood cells, white blood cells and platelets. 
Platelets help our body form clots to stop bleeding.
If one of the blood vessels gets damaged, it sends out signals that are picked up by platelets. The platelets then rush to the site of damage and form a plug, or clot, to repair the damage.

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Instrument: 1 Mark
Working: 1 Mark
The walls of the chambers of the heart are made up of muscles. These muscles contract and relax rhythmically. The rhythmic contraction of muscles is followed by its relaxation. This constitutes a heartbeat.
The doctors use a stethoscope to listen to the heartbeat. It amplifies the sound of the heartbeats which makes it easier for the doctors to listen.