🌍 Environment & Ecology MCQ Questions
Set – 3 | Competitive Examinations
Best for exams where Environment & Ecology has high relevance
Q21. Which gas is primarily responsible for the greenhouse effect?
- (A) Oxygen
- (B) Carbon dioxide
- (C) Nitrogen
- (D) Hydrogen
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Correct answer is Carbon dioxide. It traps heat in the atmosphere, contributing to global warming.
Q22. Which of the following is a renewable source of energy?
- (A) Solar energy
- (B) Coal
- (C) Petroleum
- (D) Natural gas
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Correct answer is Solar energy. It is inexhaustible and available worldwide.
Q23. Which layer of the atmosphere protects Earth from harmful ultraviolet rays?
- (A) Troposphere
- (B) Stratosphere
- (C) Mesosphere
- (D) Thermosphere
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Correct answer is Stratosphere. The ozone layer in this layer absorbs harmful UV radiation.
Q24. Eutrophication in water bodies is mainly caused by:
- (A) Excess nutrients
- (B) Plastic waste
- (C) Oil spills
- (D) Thermal pollution
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Correct answer is Excess nutrients. Runoff from fertilizers leads to algal blooms and oxygen depletion.
Q25. Deforestation affects the environment by:
- (A) Producing oxygen
- (B) Reducing sunlight
- (C) Increasing rainfall
- (D) Increasing CO₂ levels
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Correct answer is Increasing CO₂ levels. Removing trees reduces CO₂ absorption, contributing to climate change.
Q26. The main component of acid rain is:
- (A) Sulfuric acid
- (B) Nitric oxide
- (C) Carbonic acid
- (D) Hydrochloric acid
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Correct answer is Sulfuric acid. Formed when sulfur dioxide reacts with atmospheric water.
Q27. Which human activity contributes most to global warming?
- (A) Burning fossil fuels
- (B) Planting trees
- (C) Using solar panels
- (D) Recycling
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Correct answer is Burning fossil fuels. It releases large amounts of CO₂ into the atmosphere.
Q28. The term “carbon footprint” refers to:
- (A) Soil erosion
- (B) Water usage
- (C) Total greenhouse gas emissions
- (D) Forest area loss
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Correct answer is Total greenhouse gas emissions. It measures human impact on climate change.
Q29. Which international agreement aims to limit global carbon emissions?
- (A) Paris Agreement
- (B) Montreal Protocol
- (C) Kyoto Protocol
- (D) Rio Declaration
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Correct answer is Paris Agreement. It is a global treaty to reduce greenhouse gas emissions.
Q30. Which process removes carbon dioxide from the atmosphere?
- (A) Photosynthesis
- (B) Respiration
- (C) Combustion
- (D) Decomposition
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Correct answer is Photosynthesis. Plants remove CO₂ from the atmosphere and produce oxygen.
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