31. What is the role of oceans in the carbon cycle?
- A. Absorbing CO₂ from the atmosphere
- B. Producing greenhouse gases
- C. Reducing global warming by increasing temperature
- D. Storing nitrogen from fertilizers
Answer: A. Absorbing CO₂ from the atmosphere
Explanation:
Oceans act as a carbon sink, absorbing CO₂ from the atmosphere, which helps moderate the increase in atmospheric CO₂ levels. However, this also contributes to ocean acidification.
32. Which of the following is considered a feedback loop that amplifies global warming?
- A. Increased cloud cover
- B. Ice-albedo feedback
- C. Volcanic eruptions
- D. Solar flares
Answer: B. Ice-albedo feedback
Explanation:
The ice-albedo feedback is a positive feedback loop where the melting of ice reduces the Earth’s reflectivity (albedo), causing more heat to be absorbed, which accelerates further melting and warming.
33. Which of the following gases is removed from the atmosphere by photosynthesis?
- A. Oxygen (O₂)
- B. Carbon dioxide (CO₂)
- C. Nitrogen (N₂)
- D. Methane (CH₄)
Answer: B. Carbon dioxide (CO₂)
Explanation:
Photosynthesis in plants removes carbon dioxide (CO₂) from the atmosphere and converts it into oxygen and glucose, playing a crucial role in reducing atmospheric CO₂ levels.
34. Which of the following will likely decrease due to global warming?
- A. Ocean temperatures
- B. Glacier size
- C. Sea level
- D. Frequency of heatwaves
Answer: B. Glacier size
Explanation:
Global warming causes glaciers to melt, leading to a decrease in glacier size. This contributes to rising sea levels and loss of freshwater reserves.
35. Which gas, although a greenhouse gas, is naturally the most abundant in the atmosphere?
- A. Carbon dioxide (CO₂)
- B. Nitrogen (N₂)
- C. Water vapor (H₂O)
- D. Ozone (O₃)
Answer: C. Water vapor (H₂O)
Explanation:
Water vapor is the most abundant greenhouse gas in the atmosphere, but its concentration is not directly controlled by human activities. It plays a critical role in the natural greenhouse effect.
36. Which type of energy production contributes the least to global warming?
- A. Coal power plants
- B. Nuclear energy
- C. Hydroelectric dams
- D. Solar power
Answer: D. Solar power
Explanation:
Solar power is a renewable energy source that does not produce greenhouse gases during its operation, making it one of the least contributors to global warming.
37. Which of the following gases contributes to both the greenhouse effect and ozone layer depletion?
- A. Carbon dioxide (CO₂)
- B. Methane (CH₄)
- C. Chlorofluorocarbons (CFCs)
- D. Nitrous oxide (N₂O)
Answer: C. Chlorofluorocarbons (CFCs)
Explanation:
Chlorofluorocarbons (CFCs) are potent greenhouse gases and also contribute to ozone layer depletion by releasing chlorine atoms in the stratosphere, which destroy ozone molecules.
38. The term “carbon footprint” refers to:
- A. The amount of carbon dioxide absorbed by trees
- B. The total emissions of carbon dioxide by a person or group
- C. The carbon found in Earth’s crust
- D. The total emissions of all greenhouse gases except CO₂
Answer: B. The total emissions of carbon dioxide by a person or group
Explanation:
A carbon footprint refers to the total amount of carbon dioxide emissions (and other greenhouse gases) produced by a person, organization, or event, usually measured in tons of CO₂.
39. Which of the following phenomena is directly responsible for coral bleaching?
- A. Ocean acidification
- B. Increase in ocean temperature
- C. Decrease in salinity
- D. Overfishing
Answer: B. Increase in ocean temperature
Explanation:
Coral bleaching occurs when ocean temperatures rise, causing corals to expel the symbiotic algae (zooxanthellae) living in their tissues. This leads to the loss of color and eventual death if temperatures do not return to normal.
40. Which of the following is a significant cause of deforestation and contributes to global warming?
- A. Agriculture expansion
- B. Urban development
- C. Illegal logging
- D. All of the above
Answer: D. All of the above
Explanation:
Deforestation is driven by factors such as agriculture expansion, urban development, and illegal logging. These activities reduce the number of trees that absorb CO₂, thus contributing to global warming.
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