Answer:
The stratosphere contains 9.9% of air mass over the Earth. 90% of the ozone layer is found in the stratosphere's upper crust. For more information, look it up. Oh and by the way, airplanes fly in this layer. Hope this helps. Good luck on anything your doing. Please mark brainliest if you feel like it, I would really appreciate it.
"The stratosphere is a layer of Earth's atmosphere. It is the second layer of the atmosphere as you go upward. ... Ozone, an unusual type of oxygen molecule that is relatively abundant in the stratosphere, heats this layer as it absorbs energy from incoming ultraviolet radiation from the Sun."
