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Waste products: 1 Mark
Main excretory product: 1 Mark
Sweat: 1 Mark
The urine consists of 95% water, 2.5 % urea and 2.5% other waste products. Urea is the major excretory product in humans. Extra salts are removed along with water as sweat.

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Each description: 1 Mark
Blood pressure is the pressure exerted by blood on the walls of the arteries.
The throbbing movement is called pulse and it is due to the blood flowing in the arteries.
The number of beats per minute is called the pulse rate. A resting person usually has a pulse rate between72 and 80 beats per minute.

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Excretion: 1 Mark
Components: 2 Marks
Functions: 2 Marks
During various activities which are performed within the cells in the body, certain by-products are produced.Some of these products are toxic and are required to be thrown out. This is the reason why excretion is required.
The various components of the excretory system of humans include a pair of kidney, ureter, urinary bladder and the urethra.
Kidneys are the structures where the purification of blood occurs. From the kidneys, the urine goes into the urinary bladder through tube-like structures called ureters.It isstored in the urinary bladder and is passed out through the urinary opening at the end of a muscular tube called urethra.

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Naming: 1 Mark
Function: 1 Mark
Haemoglobin is the pigment which gives red colour to the blood in animals.
It carries oxygen to all the parts of the body.

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Each component: 0.5 Marks
The components of blood are:
(i) Plasma
(ii) Red blood cells (RBC)
(iii) White blood cells (WBC)
(iv) Platelets

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Each point: 1 Mark
$\begin{array}{cc}RBC& WBC\\ 1.Theyareredincolour.& 1.Theyarecolourless.\\ 2.Theyhavehaemoglobin.& 2.Theylackhaemoglobin.\\ 3.Theyhelpintransportofgases.& 3.Theyhelpinfightingagainstgermsandinfection.\end{array}$

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Each point: 1 Mark
(i) It carries oxygen to all the parts of the body and also carries carbon dioxide back to the lungs to be expelled.
(ii) It carries digested food to various parts of the body for absorption.
(iii) It contains platelets which help in the clotting of blood.
(iv) It helps in maintaining constant body temperature.
(v) It transports hormones.
(vi) Ithelps in fighting the body with germs and bacteria.

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Each point: 1 Mark
Xylemis one of the two types of vasculartissues in plants, phloem being the other. The function of xylem is totransportwater and nutrients from the roots to all parts of the body.

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Each point: 1 Mark
Kidney is the organ responsible for purification of blood. The major excretory product in humans is urea. Urea, excess water and other waste products arefiltered fromthe bloodby kidneys. Kidneys produce urine which has all these wastes and is thrown out while urination.

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Each point: 1 Mark
1. Veins are the vessels which carry blood to the heart.
2.Arteries are the vessels which carry blood away from the heart.
3. Pulmonary vein is the blood vessel that brings oxygenated blood to the human heart.
4. Right chamber of the human heart comprising of right atrium and right ventricle receives deoxygenated blood from all the parts of the body.
5. De-oxygenated blood comes from the body to the upper chamber on the right, the right atrium, as it expands. Then it contracts to transfer the blood to the right ventricle causing it to dilate. The right ventricle, in turn, pumps it to the lungs for oxygenation which is brought back to left atrium by pulmonary vein. Itis then pumped to the rest of the body by aorta.