The atmosphere of the Earth is heated by radiations which are mainly (a) radiated by the Sun (b) re-radiated by land (c) re-radiated by water (d) re-radiated by land and water
re-radiated by land and water
One of the following processes is not a step involved in the water-cycle operating in nature (a) evaporation (b) transpiration (c) precipitation (d) photosynthesis
Photosynthesis
Which of the following is not a greenhouse gas? (a) Methane (b) Carbon dioxide (c) Carbon monoxide (d) Ammonia
Ammonia
‘Ozone-hole’ means (a) a large sized hole in the ozone layer (b) thinning of the ozone layer (c) small holes scattered in the ozone layer (d) thickening of ozone in the ozone layer
Thinning of Ozone Layer
Top-soil contains the following (а) Humus and living organisms only (b) Humus and soil particles only (c) Humus, living organisms and plants (d) Humus, living organisms and soil particles.
Humus, living organisms and soil particles.
Major source of mineral in soil is the (a) parent rock from which soil is formed (b) plants (c) animals (d) bacteria
parent rock from which soil is formed
Total Earth’s surface covered by water is (a) 75% (b) 60% (c) 85% (d) 50%
75%
Biotic component of the biosphere is not constituted by (a) producers (b) consumers (c) decomposer (d) air
air
Oxygen is returned to the atmosphere mainly by (a) burning of fossil fuel (b) respiration (c) photosynthesis (d) fungi
photosynthesis
Growth of lichens on barren rocks is followed by the growth of (a) moss (b) ferns (c) gymnosperms (d) algae
Mosses
Marked temperature changes in an aquatic environment can affect (a) breeding of animals (b) more growth of aquatic plants (c) process of digestion in animals (d) availability of nutrients.
breeding of animals
Soil erosion can be prevented by (a) raising forests (b) deforestation (c) excessive use of fertiliser (d) overgrazing by animals
raising forests
Oxygen is harmful for (a) ferns (b) nitrogen fixing bacteria (c) chara (d) mango tree
(b) nitrogen fixing bacteria
The temperature ranges from …………… to …………… on the moon as it does not have atmosphere.
-190° C, 110° C
