Which of the following water pollutants is most harmful to human health?
a) Phosphates
b) Lead
c) Silicates
d) Nitrates
Answer: b) Lead

What is the main reason for the scarcity of freshwater on Earth?
a) Pollution
b) Overuse
c) Climate change
d) All of the above
Answer: d) All of the above

Which type of water is best suited for industrial processes?
a) Hard water
b) Soft water
c) Distilled water
d) Saltwater
Answer: b) Soft water

What is the process by which water enters the atmosphere from plant leaves?
a) Evaporation
b) Transpiration
c) Condensation
d) Infiltration
Answer: b) Transpiration

Which of the following is a method of conserving water?
a) Over-irrigation
b) Water recycling
c) Industrial discharge
d) Deforestation
Answer: b) Water recycling

The presence of excessive algae in water bodies is primarily due to:
a) Oil spills
b) Eutrophication
c) Acid rain
d) Thermal pollution
Answer: b) Eutrophication

Which substance is commonly used to disinfect water in water treatment plants?
a) Chlorine
b) Ammonia
c) Sulfur
d) Sodium
Answer: a) Chlorine

What does the term “potable water” refer to?
a) Contaminated water
b) Salty water
c) Drinking water
d) Polluted water
Answer: c) Drinking water

Which of the following is the largest freshwater lake by volume?
a) Lake Superior
b) Lake Victoria
c) Lake Baikal
d) Lake Michigan
Answer: c) Lake Baikal

What is the main source of groundwater?
a) Oceans
b) Rivers
c) Rainfall
d) Lakes
Answer: c) Rainfall