Global warming can lead to melting polar ice and rising sea levels, in part due to which effect?

• A. Increased volcanic activity
• B. Ambient cool temperatures
• C. The greenhouse effect
• D. The ozone layer recovery

Answer: (C)

The main idea here is how increasing greenhouse gases trap heat in the atmosphere. Sunlight warms the Earth, but heat would normally escape back to space as infrared radiation. Greenhouse gases like carbon dioxide and methane absorb a lot of that infrared energy and bounce heat back toward the surface, warming the planet. This extra warming melts polar ice and causes seawater to expand, both contributing to higher sea levels.

Other options don’t fit the mechanism. Volcanic activity can inject particles that may cool or temporarily alter climate, not drive long-term warming. Ambient cool temperatures would oppose warming, so that’s the opposite of what happens. Ozone layer recovery changes UV exposure but doesn’t explain a broad, long-term rise in global temperatures and sea levels.