1. India has more than 50,000 strains of rice. Mention the level of biodiversity it represents. [2010] Ans. It is a genetic variation within the species. 2. Mention the information that the health workers derive by measuring BOD of a water body. [2009] Ans. BOD (Biological Oxygen Demand) is the amount of oxygen required for biological oxidation of microbes in any unit volume of water. 3. State an instance where human intervention saved the forest from destruction. [2009] Ans. Chipko movement. 4. Name any two forest products, each of which is the basis for some industry. [2009] Ans. 1. Wood : Sports, furniture and paper manufacturing. 2. Resin : Turpentine industry. 5. Why are coal and petroleum considered to be non-renewable sources of energy? [2009] Ans. Coal and petroleum are considered non-renewable sources of energy because they are not being formed continuously in nature and are, therefore, not replenished. Continuous use wil...