(i) Problem might be in the blood circulation through the heart from different body organs and vice-versa.
(ii) Approximately the heart is of the size of our fist.
(iii) Blood is red in colour due to the red pigment known as haemoglobin.
(iv) Though it is the professional ethics, still as a human the doctor showed his awareness, application of common sense and above all his knowledge to save one's life.

Blood is a fluid which flows in blood vessels.
(a) Functions of blood :
(i) It transports digested food from small intestine to all parts of the body. 
(ii) It carries oxygen from lungs to cell.
(b) Components of blood:
(i) Fluid: Plasma
(ii) Cells: RBC,WBC, Platelets.

Blood is a liquid which is composed of following two parts:
(i) Plasma: The fluid part of the blood is called plasma.
(ii) Cells: There are three kinds of cells suspended in the plasma of blood
(a) Red Blood cells (RBC): These cells contain a red pigment called haemoglobin. Haemoglobin binds with oxygen and transports it to all the parts of the body and ultimately to all cells. It will be difficult to provide oxygen efficiently to all the cells of the body without haemoglobin. Due to the presence of haemoglobin the blood appears red.

(b) Platelets: The third type of cells found in the blood are platelets. Their function is to form clot to prevent loss of blood when we are injured. 
(c) White Blood Cells (WBC): WBCs fight against germs that may enter our body and thus protect us from infection.

A-Septum between right and left side of heart. It prevents mixing of oxygenated and deoxygenated blood.
B-Left ventricle,which pumps oxygenated blood to body parts.
C-Aorta is the main artery emerging from left ventricle. It gives rise to other arteries which carry blood to different body parts.
D-Left auricles, which receives oxygenated blood from lungs and pushes it into left ventricle.
E-Pulmonary vein brings oxygenated blood from lungs to left auricle.

Kidney have coiled structures (nephrons) surrounded by blood capillaries. When blood passes from them, all useful and harmful substance are filtered from blood. While passing through the capillaries all the useful substance present in filtered fluid are reabsorbed by blood. The waste product urine is then passed into urinary bladder through ureter. When the bladder is full, the same is removed through urethra.

The terms on the basis of the categories can be grouped as follows
(a) Circulatory system of human
         Arteries, atria, capillaries, veins, heart.
(b) Excretory system in human
         Urethra, kidneys, ureter, urinary bladder.
(c) Transport of substances in plants
         Root hairs, xylem, phloem.

(a) Bleeding stops after some time because some specialised cells start forming a hard covering called clot at the site of wound.
(b) Bleeding is a fluid connective tissue present in all parts of the body. Platelets are responsible for formation of clot.
(c) Mansi is helpful, knowledgeable and interested in science subject.

(a) When a cut or wound starts bleeding after some time, a clot is formed which plugs the cut and bleeding stops.
(b) Wounded area becomes dark red in colour due to clotting of blood.
(c) The blood clot is formed due to the presence of the cells called platelets in the blood.

(a) Dialysis is the process used for cleaning of the blood by separating the waste products in an artificial medium.
(b) Dialysis is needed when the excretory organ of humans, i.e. kidney becomes damaged on unfunctional due to some injury or infection.
(c) Excretion process removes the waste products released in body after the utilisation of food and other components. These products are toxic and may harm us if not removed from our body.
(d) Kidney
(e) Priya is curious, sincere and aware eager to acquire new knowledge.