Natural Resources : Previous Year's Questions

1 Mark Questions


Q.1 What is smog?                                                                    

[CBSE (CCE), 2012]

Smog is a combination of smoke and fog. This is formed due to the condensation of fog on the carbon particles present in the smoke that is produced due to the combustion of domestic fuels and industrial fuels like coal and petroleum. It lowers the visibility during the winter season and is an indication of air pollution.

Q.2  Name the free living nitrogen fixing bacteria.              

[CBSE (CCE), 2012]

Free-living (non-symbiotic) bacteria, cyanobacteria (or blue-green algae) Anabaena and Nostoc. Mutualistic (symbiotic) bacteria such as Rhizobium, associated with leguminous plants.

Q.3 State two factors responsible for weathering of rocks.                              

[CBSE (CCE), 2012]

Two factors responsible for weathering of rocks are: 

(a) Climate conditions- It includes the meteorological elements effect on rocks such as moisture, temperature, and wind and air pressure

(b) Topography and vegetation- Topography directly effects weathering by exposing rocks to the temperature or sun and wind. The elevated areas will be affected more and low level areas will be affected less

(c) Composition-There are certain elements which are included in rock composition. Some rocks will weather quickly and some slowly e.g. acidic rocks weather more quickly than basic ones. Surface covered by the vegetation are protected from weathering but bare surfaces are weathered to great extent. 

Q.4 Mention the two processes in which oxygen is used up from the atmosphere and the only process in which it is returned to the atmosphere.

[CBSE, 2011]

(i) Respiration and Combustion

(ii) Photosynthesis

Q.5 Write the two biotic components of the biosphere.             

[CBSE (CCE), 2011]

The biotic components of biosphere are plants, animals and microorganisms.

Q.6 How is CO2 fixed in the atmosphere?                                     

[CBSE (CCE), 2011]

It is fixed in many ways:

(a) During the process of respiration in humans and animals, carbon dioxide released into the atmosphere as a by-product

(b) Decomposition is the largest source through which carbon is returned to the atmosphere as carbon

(c) Weathering of rocks.

(d) By burning the fossil fuels

(e) From Volcanic eruptions


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