B-coli or E-coli are harmless organisms but their presence in water indicates the

Related MCQs

• The presence of calcium and magnesium bi-carbonates in water causes hardness in the water.
• The presence of calcium and magnesium chloride in water causes
• The presence of hydrogen sulphide in water causes
• The presence of bacteria in water causes
• The presence of carbon dioxide in water causes acidity.
• A valve which allows the water to flow in one direction but prevents its flow in the reverse direction, is known as
• The presence of
• The amount of water collected in a reservoir is divided into three portions and the order of their existance from bottom to the top is
• The most important source of water for public water supply is
• The water obtained from a lake is known as surface water.