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

Draw a labelled diagram of:

1. A xylem vessel.
2. A sieve tube (or phloem).

How is double circulation different from single circulation?

1. Mention any two components of blood.
2. Trace the movement of oxygenated blood in the body.
3. Write the function of valves present in between atria and ventricles.
4. Write one structural difference between the composition of artery and veins.

There is a pair of bean-shaped organs P in the human body towards the back, just above the waist. A waste product Q formed by the decomposition of unused proteins in the liver is brought into organ P through blood by an artery R. The numerous tiny filters S present in organ P clean the dirty blood by removing the waste product Q. The clean blood goes into circulation through a vein T. The waste substance Q, other waste salts, and excess water form a yellowish liquid U which goes from organ P into a bag-like structure V through two tubes W. This liquid is then thrown out of the body through a tube X.

1. What is (i) organ P and (ii) waste substance Q?
2. Name (i) artery R, and (ii) vein T.
3. What are tiny filters S known as?
4. Name (i) liquid U, (ii) structure V, (iii) tubes W and (iv) tube X.

What is the main difference between aerobic respiration and anaerobic respiration? Give one example of each.

Write the difference between nutrition in plants and animals.

The transport system in plants consists of two kinds of tissues X and Y. The tissue X is made up of living cells and consists of two components A and B. The component A has tiny pores in its end walls and contains only cytoplasm but no nucleus. On the other hand, component B has cytoplasm as well as nucleus. The tissue Y is made up of dead cells and consists of two components C and D. The component C has open ends whereas component D does not have open ends. In flowering plants, either only C or both C and D transport water but D is the only water conducting tissue in non - flowering plants.

1. What is (i) tissue X, (ii) component A and (iii) component B?
2. What is (i) tissue Y, (ii) component C and (iii) component D?

Describe the exchange of gases which takes place in the leaves of a plant:

1. During daytime.
2. At night.

In the artificial kidneys, the tubes are all with semi-permeable lining. Why?