Answer:
Light travels fast in air but i dont know about water
Less than it’s diameter at the equator
Troposphere. The troposphere is the lowest layer of our atmosphere.
Stratosphere. The infamous ozone layer is found within the stratosphere.
Mesosphere. Most meteors burn up in the mesosphere.
Thermosphere. Many satellites actually orbit Earth within the thermosphere
Exosphere. Considered to be the actual "final frontier"
Ionosphere. The electrically charged atoms and molecules that are formed in this way are called ions, giving the ionosphere its name