1. Temperature cools about 6.5 degrees Celsius per kilometer of _______.

2. ___________ from 10 km to 50 km about Earth, this layer contains ozone that absorbs much of the Sun's ultraviolet radiation. It contains most clouds and ____________.
3. _______ layers include the mesosphere (50 to 85 km about surface), thermosphere (85 to 500 km above surface, and the exosphere.
4.