Q. Which of the following claims about compressed natural gas is correct? It is a clean fuel It is a harmful fuel It is a polluting fuel All of the above Answer: It is a clean fuel

Q. Which of the following is the effect of high BOD? More birth of aquatic plants More birth of fishes Higher dissolved oxygen Lower dissolved oxygen Answer: Lower dissolved oxygen

Q. What do BOD and COD stand for? Biological Oxygen Demand and Chemical Oxygen Demand respectively Chemical Oxygen Demand and Biological Oxygen Demand respectively Botanical Oxygen Demand and Chemical Oxygen Demand respectively Basic Oxygen Demand and Chemical Oxygen Demand respectively Answer: Biological Oxygen Demand and Chemical Oxygen Demand respectively

Q. What is the excess growth of plankton in water due to the presence of nutrients called? Fungal bloom Algal bloom Plantae bloom Animal bloom Answer: Algal bloom

Q. Who utilizes the maximum amount of oxygen in the upstream of sewage discharge? Animals Microorganisms Humans Plants Answer: Microorganisms

Q. What happens when the maximum amount of oxygen in the upstream of sewage discharge is utilized by microbes? Natality of aquatic plants Natality of aquatic fishes Mortality of aquatic creatures Mortality of bacteria Answer: Mortality of aquatic creatures

Q. How is the amount of biodegradable organic matter in sewage water estimated? Chemical Oxygen Demand Physical Oxygen Demand Biological Oxygen Demand Mathematical Oxygen Demand Answer: Biological Oxygen Demand

Q. Which sewage contains biodegradable waste such as organic matter? Medical waste Plastic waste Domestic waste Wild waste Answer: Domestic waste

Q. Who is responsible for the degradation of biodegradable organic matter present in the domestic sewage? Animals Humans Plastic Bacteria and other microbes Answer: Bacteria and other microbes

Q. Which materials are hard to remove from the polluted water? Sand Plastic Solids Dissolved salts Answer: Dissolved salts