An organism A which cannot move from one place to another, makes a simple food B from the substances C and D available in the environment. This food is made in the presence of a green coloured substance E present in organs F in the presence of light energy in a process called G. Some of the simple food B also gets converted into a complex food H for storage purposes. The food H gives a blue-black colour with dilute iodine solution.

1. What is (i) organism A, (ii) food B and (iii) food H?
2. What are C and D?
3. Name (i) green coloured substance E, and (ii) organ F.
4. What is the process G?

When a person eats sugary food, then organisms A present in his mouth act on sugar to produce a substance B. The substance B first dissolves the calcium salts from the top part C of the tooth and then from its middle part D forming holes E. These holes ultimately reach the part F in the lower part of tooth which contains nerves and blood vessels. The substance B irritates the nerve endings inside the tooth causing toothache.

1. What are (i) organisms A, and (ii) substance B?
2. What are (i) part C, and (ii) part D, of tooth known as?
3. By what name are the holes E in the tooth known?
4. Name the part F of the tooth.
5. What will happen if organisms A reach part F of the tooth known?

Explain the digestion of chapati in human beings. Draw a diagram depicting human alimentary canal.

Draw the diagram of alimentary canal of man and label the following parts.Mouth, Oesophagus, Stomach, Intestine.

Draw a schematic representation of transport and exchange of oxygen and carbon dioxide during transportation of blood in human beings and label on it, Lung capillaries, Pulmonary artery to lungs Aorta to body, Pulmonary veins from lungs.

Where does anaerobic respiration occur in human body?

‘Aerobic respiration produces more ATP than anaerobic respiration’. Justify this statement.

Some sugar solution is taken in a test-tube and a little of substance X in powder form is added to it. The mouth of test - tube is closed with a cork and allowed to stand for sometime. On opening the cork, a characteristic smell of substance Y is obtained and a gas Z is also observed to be formed. The gas Z extinguishes a burning matchstick.

1. What could be X, Y and Z?
2. What is the process of converting sugar into substance Y by the action of X known as?
3. What type of respiration is exhibited by X in the above process?

1. Draw a sectional view of the human heart and label on it: Aorta, Pulmonary arteries, Vena cava, Left ventricle.
2. Why is double circulation of blood necessary in human beings?

1. Define excretion.
2. Name the basic filtration unit present in the kidney.
3. Draw excretory system in human beings and label the following organs of excretory system which perform following functions:

1. Form urine.
2. Is a long tube which collects urine from kidney.
3. Store urine until it is passed out.