Tag: environment and conservation

Soil pollution is caused by the addition of substances which decrease its productivity. It is caused by agrochemicals, industrial wastes, municipal wastes etc. It adversely affects the fertility of the soil. Pesticides are used in agricultural practices and these chemicals penetrate into the soil and changes the pH of the soil. Also, pesticides affect the fertility of soil by decreasing the number of soil microorganisms. 

SPM (Suspended Particulate Matter) is defined as particles floating in the air with a diameter below 10um. Studies have shown that high SPM concentrations in the air can have a detrimental impact on respiratory organs. SPM is generated both from natural sources (e.g.,volcanoes or dust storms) and human activities (vehicles, incinerators and industrial plants)

Catalytic converter is a device designed to reduce the amount of emissions from automobiles.The current (so - called three - way) systems use a heated metal catalyst to reduce the emissions of carbon monoxide CO),hydrocarbons and nitric oxide (NO), all of which contribute to the formation of photochemical smog. In an automobile's exhaust system, a catalytic converter provides an environment for a chemical reaction where unburned hydrocarbons undergoes complete combustion. Hence the combustion process continues but outside the engine combustion chamber where no useful energy is extracted.Toxic car gases such as unburned hydrocarbon (UHC) and carbon monoxide(CO) would not exist if the fuel to energy conversion in the engine were perfect.

So, the correct answer is 'If both the assertion and reason are true but the reason is not a correct explanation of the assertion'

Photosynthesis, process by which green plants and certain other organisms use the energy of light to convert carbon dioxide and water into the simple sugar glucose. In so doing, photosynthesis provides the basic energy source for virtually all organisms. So, the correct option is "D" (Photosynthesis).