Final answer:
The mesosphere is known to be the coldest layer of Earth's atmosphere. It does not typically contain visible clouds at night nor does it have windstorms exceeding 320 kmph. Therefore, the correct answer to the question is C) It is the coldest layer of the atmosphere.
Step-by-step explanation:
The mesosphere is one of the five layers of the Earth's atmosphere. Answering the question, which of the following is true of the mesosphere: A) It contains clouds that are visible at night. B) Windstorms involving wind velocities in excess of 320 kmph (200 mph) occur in this layer. C) It is the coldest layer of the atmosphere. D) All of the above are true. E) None of the above are true.
The correct answer is C) It is the coldest layer of the atmosphere. While the mesosphere does have unique characteristics, such as being the layer where meteors burn up, it is incorrect to state that it contains clouds visible at night, or that it regularly has windstorms with velocities exceeding 320 kmph. Most atmospheric wind and weather are confined to the troposphere, the lowest layer. The mesosphere starts above the stratosphere and extends up to 85 kilometers high, and temperatures there decrease with altitude, making it the coldest atmospheric layer.