Without the greenhouse effect, Earth's oceans would be

• A. Frozen
• B. Warmer
• C. Unchanged
• D. Boiling away

Answer: (A)

The key idea is how the greenhouse effect acts like a warming blanket for Earth. Greenhouse gases trap heat that would otherwise radiate back into space, keeping the average surface temperature much higher than it would be otherwise. Without that heat-trapping layer, the planet would cool dramatically.

If the greenhouse effect were removed, solar energy would still reach Earth, but infrared radiation would escape more easily. The global average temperature would drop by tens of degrees, so the oceans would cool and freeze at the surface. While deep waters might stay liquid for a time due to heat from the planet’s interior, the bulk of the oceans would be frozen in this scenario.

So the best answer is that the oceans would be frozen. The other options imply warming, no change, or boiling, which don’t fit the consequence of removing the greenhouse effect.