A. Files
B. Algae
C. Micro-organisms
D. Mosquitoes
Related Mcqs:
- Presence of iron and manganese in water causes___________________?
A. Reduction in its dissolved oxygen content
B. Discoloration of bathroom fixtures
C. Temporary hardness
D. None of these - Iron & manganese present as pollutant in water cannot be removed by__________________?
A. Ion exchange process
B. Oxidation followed by settling & filtration
C. Lime soda process or manganese zeolite process
D. Chlorination - Iron & manganese present in the polluted water is removed by __________________?
A. Simple filtration
B. Oxidation followed by settling & filtration
C. Chemical coagulation
D. Chlorination only - Fluorosis is caused due to the presence of excessive amount of ______________ in drinking water?
A. Mercury
B. Lead
C. Fluoride
D. Arsenic - Presence of dissolved impurities of ______________ is responsible for the red brownish color of water?
A. Carbonates
B. Bi-carbonates
C. Iron & manganese
D. Arsenic - Thermal pollution of water increases its toxicity and oxidation of oxygen demanding waste besides favouring bacterial growth. A rise in water temperature by 10°C, doubles the toxic effects of _____________ present in it?
A. Coal ash
B. Potassium cyanide
C. Ortho-xylene
D. None of these - Presence of _____________ bacteria in water causes disease like typhoid?
A. Aerobic
B. Pathogenic
C. Anaerobic
D. Non-pathogenic - Presence of bacteria in potable (drinking) water causes_________________?
A. Turbidity
B. Disease
C. Bad odour
D. Bad taste & colour - Presence of nitrogen and phosphorous in waste water discharged into lakes and ponds causes_______________?
A. Foaming
B. Odour nuisances
C. Undesirable plant growth
D. Turbidity - Presence of excess fluorine in water causes__________________?
A. Dental cavity
B. Tooth decay
C. Fluorosis
D. Respiratory disease
