A, B and C are three living organisms. The organism A is a unicellullar fungus which can live without air. It is used in the commercial production of an organic compound P from molasses. The organism B is a unicellular animal which lives in water and feeds and moves by using pseudopodia. It breathes through an organelle Q. The organism C is a tiny animal which acts as a carrier of malarial parasite. It breathes and respires through a kind of tiny holes R and air - tubes S in its body.

1. What are organisms A, B and C?
2. Name P, Q, R and S.
3. Which organism/ organisms undergo aerobic respiration?
4. Which organism/ organisms undergo anaerobic respiration?

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

Draw a labelled diagram of the human digestive system. With the help of this diagram, describe the process of digestion of food in man (humans).

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?

Each and every respiration organ is structurally specialised in its function. Justify with examples.

Platelets help in clotting of blood at injured side. Draw a flow diagram of this process.

1. List the three events that accur during the process of photosynthesis. Explain the role of stomata in this process.
2. Describe an experiment to show that ''sunlight is essential for photosynthesis.''

When a person puts food in his mouth, then teeth cut it into small pieces, chew and grind it. The glands A in the mouth secrete a substance B which is mixed with the food by tongue. The substance B contains an enzyme C which starts the digestion of food in the mouth. The slightly digested food from the mouth goes down a tube D. The special type of movements E in the walls of tube D push the food into stomach for further digestion. The stomach wall secretes gastric juice containing three substance F, G and H. One of the functions of F is to kill bacteria which may enter the stomach with food. The substance G protects the inside layer of stomach from the damaging effect of substance F whereas substance H is and enzyme for digestion. The partially digested food then enters into small intestine for further digestion.

1. What is Gland A, Substance B and Enzyme C?
2. Name the tube D.
3. What is the movement E known as?
4. What are F, G and H?

Explain the principle of dialysis with the help of a labelled diagram.

1. Draw a sectional view of the human heart and label on it, Aorta, Right Ventricle and Pulmonary Veins.
2. State the functions of the following components of transport system:

1. Blood.
2. Lymph.