(a) Carbon

(b) Nitrogen

(c) Phosphorus

(d) All of the above

(a) Floods

(b) Fertilizers

(c) Industrial waste

(d) Both b and c

(a) Typhoid

(b) Cholera

(c) Diarrhoea

(d) All of the above

(a) Osmosis

(b) Ion exchange

(c) Lime softening

(d) Both b and c

(a) Fluorosis

(b) Toothaches

(c) Lung disease

(d) Intestinal infection

(a) Settling

(b) Flushing

(c) Stripping

(d) Chlorination

(a) Perfumes

(b) Refrigerators

(c) Air conditioners

(d) All of the above

(a) Afforestation

(b) Oil refineries

(c) Paper factories

(d) Both b and c

(a) Magnesium sulphate

(b) Magnesium bicarbonate

(c) Magnesium carbonate

(d) None of the above

(a) It is a clean fuel

(b) It is a harmful fuel

(c) It is a polluting fuel

(d) All of the above