1. The final Agent Orange raid in Vietnam took place in 1970– areas have begun to bloom again. But 19 years after the war’s end, it seems plain that Agent Orange is killing and maiming human beings, something it never intended to do. The apparent toxic fallout from those clouds–is a crop of human miseries including cancers, miscarriages and birth defects-that may persist for decades." The offensive substance referred to in this quotation is: (a) DDT used as insecticide (b) A complex mixture of herbicides and weedicides used to increase agricultural output in the South Vietnam under the U.S. aid programme (c) A complex mixture of DDT and other insecticides used at aerial sprays for protection against malaria and other tropical diseases (d) Dioxin used as defoliants (d) America used Dioxin which is defoliants to clear the forests of Vietnam, so that is could kill the Vietnamese guerilla hiding in the forest. But the Dioxin had many after effects like cancers, miscarriage, and birth defects in after years. 2. Which one of the following fuels causes minimum environmental pollution? (a) Diesel (b) Coal (c) Hydrogen (d) Kerosene (c) Except hydrogen, all the rest three options diesel, coal and kerosene are either naturally occurring fossil fuels or derived from them. Thus as we know naturally occuring fossil fuels and their products have high percentage of carbon which on combustion lead to discharge of oxides by carbon (CO2 & CO) in air. This results in to heavy environmental pollution like CO2 results in to green house effect causes global warming While CO is poisonous in nature, it combines with haemoglobin of blood to form carboxyhaemoglobin. Hydrogen fuel as such causes no pollution because on combustion with oxygen it forms water that's why it is also called future fuel. 3. Physico-chemical characteristics of water in water sources undergo changes due to (a) aquatic macrophytes (b) aquatic fungi (c) effluents (d) evapotranspiration (c) Aquatic macrophytes, aquatic fungi are natural organism and evapotranspiration is a natural process by which plant losses water. Thus being natural they do not results into any change in physico-chemical characteristics of water while effluents discharged into water bodies by industrial units and domestic sewage results in to change in physico-chemical characteristics like pH, conductivity, temperature, electrical conductivity, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, NH4+ and NO3 ion contents etc. 4. The water pollution in river is measured by the dissolved amount of (a) Chlorine (b) Ozone (c) Nitrogen (d) Oxygen (d) Water pollution in river or any other water body is measured by amount of dissolved oxygen. Water pollution can be measured on the basis of parameters like dirtyness, change in texture, total suspended solid and other important factors like, 1. Decrease in dissolved oxygen (DO) (concentration of dissolved oxygen in water samples). 2. Increase in BOD, (Biochemical Oxygen Demand) it is a chemical procedure for determining the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. 3. Increase in COD, (Chemical Oxygen Demand) test is commonly used to indirectly measure the amount of organic compounds in water. 5. Which one of the following is produced during the formation of photochemical smog? (a) Hydrocarbons (b) Nitrogen Oxide (c) Ozone (d) Methane (c) During the photochemical smog ozone, nitric acid, PAN are produced.