Science M.C.Q. [1 M]

Wind breaks are rows of trees and shrubs on land to prevent erosion of soil by high speed wind.

The physical and chemical weathering of rocks is the process involved in formation of soil. Rocks are the naturally occurring soil aggregates of one or more minerals. For example common granite is combination of quartz, feldspar and biotite minerals.

Arid zone is characterized by areas of low rainfall and desert. Rajasthan and Gujarat fall in this zone.

These greenhouse gas emissions have increased the greenhouse effect and caused Earth's surface temperature to rise. The primary human activity affecting the amount and rate of climate change is greenhouse gas emissions from the burning of fossil fuels.

Minerals are obtained from earth's crust and the layers below it. Which then enter the biotic world through plants.

Soil erosion can be effectively prevented by methods like afforestation and reforestation.
Reforestation is the restoration of forests, which have been earlier destroyed by deforestation or other means, while afforestation is the raising of new forests.
Plants hold the soil with their roots and thus prevent the soil from any erosion.

A greenhouse gas is a gas that absorbs and emits radiant energy within the thermal infrared range. Greenhouse gases cause the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide and ozone.

Decomposition is the process of the breakdown of complex organic materials into simpler ones.

Methane, carbon dioxide and chlorofluorocarbons, all of them are greenhouse gases that trap the infrared rays and thus trap the heat, not allowing it to escape the earth’s surface, hence contributing to greenhouse effect.

Lichens are sensitive to Sulphur dioxide because they have efficient absorption systems due to which they rapidly accumulate Sulphur from high levels of Sulphur dioxide in air.

Green plants are producers in an ecosystem i.e. they produce food. The food obtained from plants is utilized by all the other components of an ecosystem. Hence, Green plants are ultimate source of energy.

Force of gravity implies percolation of water to deeper horizons in the soil. The type of soil is highly depended on the rate of percolation to take place, this is because the sandy soil dries faster than clayey soil.

Paper industry uses fuels and during of fuels like coal releases mercury that is a toxic chemical.

Humus is dark, organic material that forms in soil when plant and animal matter decays. The thick brown or black substance that remains after most of the organic litter has decomposed is called humus. Earthworms often help mix humus with minerals in the soil. Humus contains many useful nutrients for healthy soil.

Biosphere constitutes all the living beings and their relationships along with their interaction with lithosphere, hydrosphere and atmosphere.

Air is inexhaustible resource. It is present in an abundant amount and will not ever run out or deplete.

A change in pressure of the water bodies can happen because of physical causes and it does not result in contamination of water.

Bacteria and fungi are microorganisms that decompose the dead and decaying matter.

Rajendra Singh is popularly known as water man of India. He is a water conservationist from Alwar, Rajasthan.