11. Which of the following is a man-made greenhouse gas?
- A. Water vapor (H₂O)
- B. Methane (CH₄)
- C. Chlorofluorocarbons (CFCs)
- D. Carbon dioxide (CO₂)
Answer: C. Chlorofluorocarbons (CFCs)
Explanation:
Chlorofluorocarbons (CFCs) are man-made chemicals used in refrigerants and aerosols that contribute to the greenhouse effect and also cause ozone depletion. Water vapor and CO₂ are naturally occurring, although CO₂ emissions can also result from human activities.
12. Which international agreement focuses on limiting the rise in global temperatures to below 2°C above pre-industrial levels?
- A. Montreal Protocol
- B. Kyoto Protocol
- C. Paris Agreement
- D. Copenhagen Accord
Answer: C. Paris Agreement
Explanation:
The Paris Agreement was adopted in 2015 and aims to limit the rise in global average temperatures to below 2°C, with efforts to keep it below 1.5°C, by reducing greenhouse gas emissions globally.
13. Which of the following factors has the least contribution to global warming?
- A. Deforestation
- B. Industrialization
- C. Use of renewable energy sources
- D. Burning of fossil fuels
Answer: C. Use of renewable energy sources
Explanation:
The use of renewable energy sources, such as wind, solar, and hydroelectric power, contributes minimally to global warming because these energy sources do not emit greenhouse gases, unlike fossil fuels.
14. Ozone layer depletion primarily allows the increase of which harmful radiation on Earth’s surface?
- A. Infrared radiation
- B. Ultraviolet (UV) radiation
- C. X-rays
- D. Gamma rays
Answer: B. Ultraviolet (UV) radiation
Explanation:
Ozone layer depletion results in the increase of ultraviolet (UV) radiation reaching the Earth’s surface. Increased UV radiation can lead to skin cancer, cataracts, and harm to ecosystems.
15. Which sector is the largest source of anthropogenic methane emissions?
- A. Agriculture
- B. Transportation
- C. Manufacturing
- D. Energy production
Answer: A. Agriculture
Explanation:
Agriculture is the largest source of anthropogenic methane emissions, especially from livestock (enteric fermentation) and rice paddies. Methane is also released during the production and transport of coal, oil, and natural gas.
16. Which of the following is a natural source of greenhouse gas emissions?
- A. Volcanic eruptions
- B. Deforestation
- C. Burning of coal
- D. Industrial activities
Answer: A. Volcanic eruptions
Explanation:
Volcanic eruptions release natural greenhouse gases like carbon dioxide and sulfur dioxide into the atmosphere. While volcanic activity contributes to greenhouse gas emissions, human activities (like industrial activities and deforestation) are far larger contributors.
17. Which of the following human activities is most likely to cause an increase in nitrous oxide (N₂O) levels?
- A. Use of fertilizers in agriculture
- B. Combustion of fossil fuels
- C. Deforestation
- D. Urbanization
Answer: A. Use of fertilizers in agriculture
Explanation:
The use of nitrogen-based fertilizers in agriculture leads to an increase in nitrous oxide (N₂O) emissions. N₂O is a potent greenhouse gas and has a much higher global warming potential than CO₂.
18. Which of the following is not a consequence of global warming?
- A. Rising sea levels
- B. Increase in polar ice cover
- C. Coral bleaching
- D. More frequent extreme weather events
Answer: B. Increase in polar ice cover
Explanation:
Global warming leads to the melting of polar ice caps, not an increase in ice cover. Rising temperatures cause polar ice and glaciers to melt, contributing to rising sea levels.
19. Which of the following is the most potent greenhouse gas per unit of concentration?
- A. Carbon dioxide (CO₂)
- B. Water vapor (H₂O)
- C. Methane (CH₄)
- D. Nitrous oxide (N₂O)
Answer: D. Nitrous oxide (N₂O)
Explanation:
Nitrous oxide (N₂O) has a global warming potential (GWP) approximately 298 times that of CO₂ over a 100-year period, making it a more potent greenhouse gas per unit concentration, though it is present in lower quantities.
20. Which of the following contributes to the greenhouse effect but also has a cooling effect by reflecting sunlight?
- A. Aerosols
- B. Methane (CH₄)
- C. Carbon dioxide (CO₂)
- D. Nitrous oxide (N₂O)
Answer: A. Aerosols
Explanation:
Aerosols can have both a warming and cooling effect. While some aerosols can absorb heat and contribute to the greenhouse effect, others (like sulfate aerosols) reflect sunlight back into space, thus having a cooling effect.
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