Explore multiple-choice questions (MCQs) on Water Pollution and Microbial Diseases for Sainik School Exam AISSEE Class 6 GK. This study Material covers sources, effects, prevention methods, and associated diseases like cholera, typhoid, and Minamata disease. Ideal notes for exam preparation with detailed explanations.
Anand Classes multiple-choice questions (MCQs) on “Water Pollution and Microbial Diseases” for AISSEE Class 6, along with detailed answers and explanations here.
Water Pollution and Microbial Diseases – MCQs for AISSEE Class 6
1. What is water pollution?
A) Making water clean and safe to drink
B) The contamination of water bodies with harmful substances
C) Adding minerals to water
D) Purification of water
Answer: B) The contamination of water bodies with harmful substances
Explanation: Water pollution occurs when harmful substances such as chemicals, waste, and microorganisms contaminate water bodies, making them unsafe for humans, animals, and plants.
2. Which of the following is a major cause of water pollution?
A) Planting more trees
B) Dumping industrial waste into rivers
C) Drinking clean water
D) Using less water
Answer: B) Dumping industrial waste into rivers
Explanation: Factories release toxic chemicals and waste into water bodies, leading to pollution and harming aquatic life.
3. Which disease is caused by drinking contaminated water?
A) Malaria
B) Dengue
C) Cholera
D) Chickenpox
Answer: C) Cholera
Explanation: Cholera is caused by bacteria present in contaminated water, leading to severe diarrhea and dehydration.
4. What is the major source of microbial water pollution?
A) Clean rivers
B) Domestic and industrial waste
C) Fresh spring water
D) Filtered water
Answer: B) Domestic and industrial waste
Explanation: Waste from households and industries contains bacteria, viruses, and chemicals that pollute water and cause diseases.
5. Which bacteria cause typhoid?
A) Vibrio cholerae
B) Salmonella typhi
C) Escherichia coli
D) Mycobacterium tuberculosis
Answer: B) Salmonella typhi
Explanation: Typhoid fever is caused by the bacteria Salmonella typhi, which spreads through contaminated food and water.
(Previously listed questions retained…)
21. What is the main cause of algal blooms in water bodies?
A) Increased oxygen levels
B) Excessive nutrients from fertilizers and sewage
C) Presence of fish
D) Low sunlight exposure
Answer: B) Excessive nutrients from fertilizers and sewage
Explanation: When fertilizers and sewage enter water bodies, they introduce high levels of nitrogen and phosphorus, leading to rapid algae growth that depletes oxygen and harms aquatic life.
22. Which of the following is an effect of water pollution on human health?
A) Increased energy levels
B) Waterborne diseases like cholera and dysentery
C) Improved digestion
D) Stronger immune system
Answer: B) Waterborne diseases like cholera and dysentery
Explanation: Contaminated water can carry harmful microorganisms that cause diseases like cholera, dysentery, and typhoid, leading to serious health problems.
23. What happens when oil spills occur in oceans?
A) Water becomes clearer
B) Marine life is severely affected
C) Fish population increases
D) Oil dissolves quickly without any harm
Answer: B) Marine life is severely affected
Explanation: Oil spills coat marine animals, reduce oxygen levels in water, and damage ecosystems, leading to severe harm to aquatic organisms.
24. What is the purpose of water treatment plants?
A) To make water dirty
B) To purify and make water safe for drinking
C) To increase chemical pollution
D) To remove oxygen from water
Answer: B) To purify and make water safe for drinking
Explanation: Water treatment plants remove contaminants, bacteria, and harmful substances from water, making it safe for human consumption.
25. How does plastic waste affect water bodies?
A) It dissolves and disappears
B) It remains in water for years and harms marine life
C) It helps fish grow
D) It improves water quality
Answer: B) It remains in water for years and harms marine life
Explanation: Plastics do not decompose easily and can choke marine animals, release toxic chemicals, and pollute the water for a long time.
26. How does mercury pollution affect water bodies?
A) It makes water taste better
B) It is beneficial for fish
C) It accumulates in aquatic organisms and is toxic
D) It has no effect on water quality
Answer: C) It accumulates in aquatic organisms and is toxic
Explanation: Mercury is a heavy metal that enters water bodies through industrial waste. It accumulates in fish and other aquatic organisms, leading to serious health hazards when consumed by humans.
27. Which of the following is a preventive measure against waterborne diseases?
A) Drinking untreated water
B) Using open defecation
C) Proper sanitation and clean drinking water
D) Dumping waste in rivers
Answer: C) Proper sanitation and clean drinking water
Explanation: Safe drinking water, proper sanitation, and hygiene practices help prevent waterborne diseases like cholera, dysentery, and typhoid.
28. Which of the following pollutants mainly comes from agricultural activities?
A) Heavy metals
B) Pesticides and fertilizers
C) Plastic waste
D) Industrial chemicals
Answer: B) Pesticides and fertilizers
Explanation: Agricultural runoff carries pesticides and fertilizers into water bodies, leading to pollution and eutrophication.
29. What is the impact of microplastics on marine life?
A) They help fish grow
B) They are a good source of food for marine organisms
C) They enter the food chain and cause health issues
D) They clean the water
Answer: C) They enter the food chain and cause health issues
Explanation: Microplastics are tiny plastic particles that accumulate in marine life and pose serious health risks to both animals and humans when consumed.
30. What is the purpose of rainwater harvesting?
A) To waste rainwater
B) To collect and store rainwater for future use
C) To pollute water sources
D) To increase water pollution
Answer: B) To collect and store rainwater for future use
Explanation: Rainwater harvesting helps conserve water by collecting and storing rainwater for drinking, irrigation, and other uses, reducing dependence on polluted water sources.
31. How do wetlands help in reducing water pollution?
A) By adding chemicals to the water
B) By filtering pollutants and trapping sediments
C) By releasing more waste into rivers
D) By increasing water temperature
Answer: B) By filtering pollutants and trapping sediments
Explanation: Wetlands act as natural filters by trapping sediments and pollutants before they enter larger water bodies.
32. What is the main cause of acid rain, which leads to water pollution?
A) Excess oxygen in the atmosphere
B) Emission of sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) from industries and vehicles
C) Increased humidity levels
D) Planting more trees
Answer: B) Emission of sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) from industries and vehicles
Explanation: Acid rain occurs when SO₂ and NOₓ react with water vapor in the atmosphere, forming acidic precipitation that pollutes water bodies.
33. Which waterborne disease is caused by a parasite?
A) Cholera
B) Dysentery
C) Malaria
D) Giardiasis
Answer: D) Giardiasis
Explanation: Giardiasis is caused by the parasite Giardia, which spreads through contaminated drinking water.
34. What is the main disadvantage of using chlorine for water purification?
A) It makes water undrinkable
B) It produces harmful byproducts
C) It increases pollution
D) It removes all oxygen from water
Answer: B) It produces harmful byproducts
Explanation: While chlorine is effective in killing bacteria, it can produce harmful chemical byproducts that may pose health risks.
35. Which of the following is a sustainable solution to prevent water pollution?
A) Increasing chemical waste dumping
B) Using eco-friendly cleaning products
C) Destroying natural water filters like wetlands
D) Ignoring water conservation practices
Answer: B) Using eco-friendly cleaning products
Explanation: Eco-friendly products reduce harmful chemical discharge into water sources, helping to prevent pollution.
36. What is biomagnification?
A) The breakdown of pollutants in water
B) The increase in pollutant concentration as it moves up the food chain
C) The reduction of water pollution by microorganisms
D) The purification of water through evaporation
Answer: B) The increase in pollutant concentration as it moves up the food chain
Explanation: Biomagnification occurs when pollutants accumulate in organisms at higher levels in the food chain, posing risks to top predators, including humans.
37. What is the main effect of high nitrate levels in drinking water?
A) No impact on health
B) Causes Blue Baby Syndrome (methemoglobinemia)
C) Increases water clarity
D) Helps in digestion
Answer: B) Causes Blue Baby Syndrome (methemoglobinemia)
Explanation: High nitrate levels in drinking water can interfere with oxygen transport in the blood, leading to Blue Baby Syndrome in infants.
38. How do oil spills affect marine life?
A) They provide nutrients to aquatic organisms
B) They coat animals, making movement and breathing difficult
C) They clean the water by removing bacteria
D) They have no effect on marine life
Answer: B) They coat animals, making movement and breathing difficult
Explanation: Oil spills create a thick layer on water, harming marine life by reducing oxygen levels and making it difficult for animals to move and breathe.
39. What is the primary reason for treating wastewater before releasing it into the environment?
A) To add more nutrients to the water
B) To remove harmful contaminants and protect ecosystems
C) To increase water temperature
D) To reduce evaporation
Answer: B) To remove harmful contaminants and protect ecosystems
Explanation: Wastewater treatment removes pollutants before water is released back into the environment, preventing harm to aquatic ecosystems and human health.
40. Which international organization is responsible for addressing global water pollution issues?
A) NASA
B) WHO (World Health Organization)
C) FIFA
D) UNESCO
Answer: B) WHO (World Health Organization)
Explanation: WHO works to improve global water quality, promote sanitation, and reduce waterborne diseases worldwide.
41. What is the role of trees in preventing water pollution?
A) Trees increase water pollution
B) Trees absorb pollutants and reduce runoff
C) Trees release harmful chemicals into the water
D) Trees have no effect on water pollution
Answer: B) Trees absorb pollutants and reduce runoff
Explanation: Trees and vegetation help filter pollutants and reduce surface runoff, preventing contamination of water bodies.
42. What are the main sources of heavy metal pollution in water?
A) Agricultural runoff and industrial waste
B) Rainwater
C) Sea breeze
D) Drinking tap water
Answer: A) Agricultural runoff and industrial waste
Explanation: Heavy metals such as lead, mercury, and cadmium enter water bodies mainly through industrial discharge and pesticide use in agriculture.
43. How does excessive use of fertilizers affect water bodies?
A) It improves water quality
B) It leads to algal blooms and oxygen depletion
C) It reduces water pollution
D) It increases fish population
Answer: B) It leads to algal blooms and oxygen depletion
Explanation: Excess fertilizers introduce high levels of nutrients into water bodies, leading to uncontrolled algae growth and depletion of oxygen, which harms aquatic life.
44. What is reverse osmosis used for?
A) To add chemicals to water
B) To remove contaminants and purify water
C) To increase salt content in water
D) To make water undrinkable
Answer: B) To remove contaminants and purify water
Explanation: Reverse osmosis is a water purification process that removes impurities and dissolved salts, making water safe for consumption.
45. What is the major disadvantage of groundwater pollution?
A) It cleans itself quickly
B) It takes a long time to be naturally purified
C) It affects only surface water
D) It has no impact on human health
Answer: B) It takes a long time to be naturally purified
Explanation: Pollutants in groundwater can persist for many years, making it difficult and costly to clean and affecting drinking water sources.
46. What is the primary source of arsenic contamination in groundwater?
A) Air pollution
B) Natural underground rocks and industrial waste
C) Excessive rainfall
D) Plastic waste
Answer: B) Natural underground rocks and industrial waste
Explanation: Arsenic contamination mainly occurs due to natural geological sources and industrial effluents, leading to severe health hazards.
47. How does deforestation contribute to water pollution?
A) It prevents soil erosion
B) It increases soil erosion and sedimentation in water bodies
C) It improves water quality
D) It increases oxygen levels in water
Answer: B) It increases soil erosion and sedimentation in water bodies
Explanation: Trees prevent soil erosion; cutting them down leads to increased runoff and sedimentation, which pollutes water sources.
48. Which disease is caused by consuming fish contaminated with mercury?
A) Typhoid
B) Minamata disease
C) Cholera
D) Tuberculosis
Answer: B) Minamata disease
Explanation: Mercury bioaccumulates in fish and, when consumed by humans, causes Minamata disease, affecting the nervous system.
49. What is greywater?
A) Water that is completely safe for drinking
B) Wastewater from sinks, showers, and laundry
C) Water from industrial chemical waste
D) Contaminated seawater
Answer: B) Wastewater from sinks, showers, and laundry
Explanation: Greywater is wastewater that comes from domestic activities and can be treated and reused for non-drinking purposes like irrigation.
50. What is the main cause of the spread of waterborne diseases in urban areas?
A) Proper waste disposal
B) Contaminated drinking water due to poor sanitation
C) Clean water supply
D) High population density with good hygiene
Answer: B) Contaminated drinking water due to poor sanitation
Explanation: Poor sanitation leads to the mixing of sewage with drinking water, increasing the risk of waterborne diseases such as cholera and dysentery.
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