Question

Which of the following plays a very important role in the oxygen cycle?
(a) Birds
(b) Animals (c) Plants
(d) Soil
Which of the constituents of air on increasing, causes global warming?
(a) Nitrogen (b) Oxygen
(c) Carbon di oxide (d) Inert gases
The percentage of water vapour present in air is called.
(a) Density (b) Humidity (c) Mass
(d) Solubility
Lime water turns milky when exposed to air. This shows that air contains
(a) Carbon di oxide (b) Hydrogen (c) Nitrogen (d) Oxygen
Air is useful for
(a) Generating electricity
(b) the dispersal of seeds
(c) Birds flight
(d) All of the above
About one fifth of ordinary air is
(a) Nitrogen
(b) Carbon di oxide (c) Water vapour (d) Oxygen
Mountaineers carry oxygen cylinders with them because oxygen supports
(a) Combustion
(b) Oxygen is less at higher altitudes
(c) More oxygen is needed to cook food (d) Oxygen does not support combustion.
19.
20.
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DIV​

Answer 1

Answer:

(c)

(C)

(B)

(A)

(D)

(D)

(B)

Explanation:

Answer 2

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