The greenhouse gases

The correct option is A

keep the planet warm

The correct option is A

Explanation of the correct answer:

1. The atmosphere's greenhouse gases trap heat and warm the planet.
2. Carbon dioxide, methane, nitrous oxide, water vapor, and fluorinated gases are the principal greenhouse gas contributors.
3. Greenhouse gases, as a result, contribute to global warming.

Explanation of the incorrect answer:

Option B:

1. Because the glass blocks most of the heat radiation, most of it cannot leave, causing the temperature within the greenhouse to continuously rise.
2. Temperatures in a greenhouse can be warm enough for vegetables to flourish even in the winter.

Option C:

1. Because greenhouse gas molecules emit heat in all directions, part of it flows downhill and eventually returns to the Earth's surface to be absorbed.
2. The temperature of the surface rises above that of a surface heated solely by direct solar radiation.

Option D:

1. Incoming UV radiation easily passes through the glass walls of the greenhouse and is absorbed by the plants and hard surfaces within.
2. Weaker IR radiation, on the other hand, has a hard time getting through the glass walls and becomes trapped inside, warming the greenhouse.

Final answer: The greenhouse gases keep the planet warm.