Suppose last night was clear and calm. Tonight low clouds will be present. From this you would conclude that tonight’s minimum temperature will be:

The correct answer is: B. Lower than last night’s minimum temperature.

Low clouds trap heat near the ground, which can cause the temperature to drop more slowly at night. This is because the clouds reflect back some of the heat that would otherwise escape into space. On a clear night, there is nothing to trap the heat, so it can escape more easily and the temperature will drop more quickly.

Here is a more detailed explanation of each option:

• Option A: Higher than last night’s minimum temperature. This is not the correct answer because low clouds trap heat near the ground, which can cause the temperature to drop more slowly at night.
• Option B: Lower than last night’s minimum temperature. This is the correct answer because low clouds trap heat near the ground, which can cause the temperature to drop more slowly at night.
• Option C: The same as last night’s minimum temperature. This is not the correct answer because low clouds trap heat near the ground, which can cause the temperature to drop more slowly at night.
• Option D: Above freezing. This is not the correct answer because the temperature can drop below freezing even on a night with low clouds.