Plant cell lacks the mechanism of locomotion. What advantages do plants have at cellular level to compensate for the loss? Give any two examples. Take a peel of the?Tradescantia?leaf and observe it under the microscope. You will find coloured bodies in the cytoplasm of the leaf cells. What are these bodies? What is their importance in a cell? .

Chloroplasts are present exclusively in plant cells. Give reasons.

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What is the importance of the jelly-like substance present between the cell membrane and the nucleus? A student wants to study the mechanism of heredity in humans. Which cell organelle should he isolate for his study? Why? What are the forces involved in the movement of the ship in the water? Define Which type of force is used when a bird is prepared to fly? (a) List in tabular from three chemical properties on the basis of which we can differentiate between a metal and a non-metal.?
(b) Give reasons for the following:

(i) Most metals conduct electricity well.

(ii) The reaction of iron (III) oxide [Fe?2O?3] with heated aluminium is used to join cracked machine parts.

(a) Write chemical equations for the following reactions:?
??????(i) Calcium metal reacts with water.?
??????(ii) Cinnabar is heated in the presence of air.?
??????(iii) Manganese dioxide is heated with aluminium powder.? Explain the following:?
(a) Sodium chloride is an ionic compound which does not conduct electricity in solid state where as it does conduct electricity in molten state as well as in aqueous solution.?
(b) Reactivity of aluminium decrease if it is dipped in nitric acid.?
(c) Metals like calcium and magnesium are never found in their free state in nature. What would you observe on adding zinc granules to freshly prepared ferrous sulphate solution? Give reason for your answer.