Answer:
By researching, I would think that the answer is D. Ice crystals melt as they fall through a warm layer of air and then refreeze into small ice pellets as they pass through a colder layer of air.
Explanation:
<em>During precipitation formation, if temperatures are at or below freezing, 0°C (32°F), at cloud level, water in the air freezes into ice crystals, and the crystals stick together to make snow. The snow starts to fall, and if the air column is freezing cold all the way down from the clouds to the ground, the precipitation stays frozen. It simply falls as snow.</em>
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<em>Sometimes, however, a temperature inversion occurs. Normally, the temperature decreases with increasing altitude. A temperature inversion is when a layer of warm air intrudes between the ground and the clouds.</em>
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<em>Under these conditions, when the falling snow reaches the layer of warm air, it melts. Then it hits the layer of cold air just above Earth’s surface and refreezes. This all happens very fast, and the result is tiny ice pellets called sleet.</em>
