Answer:
The First layer is the troposphere. The troposphere is what we live in. It creates weather for us. Second layer is the Stratosphere. You will find the ozone layer in it. The ozone layer helps protect us from ultraviolet radiation (UV) from the sun. In fact, the ozone layer absorbs most of the UV radiation the sun sends to us. Life as we know it wouldn't be possible without this layer of protection. Third layer is Mesosphere. The Mesosphere is very important for earth's protection. The mesosphere burns up most meteors and asteroids before they are able to reach the earth's surface. Fourth layer is Thermosphere. The Thermosphere absorbs the sun radiation making it very hot.
Explanation: I don't know if you include this one but the fifth layer is the Exosphere. Although the exosphere is the most distance layer of earth's atmosphere it is the layer that is the planet's first line of defense against the sun's rays. It is also the first layer to come into contact and protect the earth from meteors, asteroids, and cosmic rays.
Answer: The force on the firefly
The unfortunate firefly hitting the bus does not change the velocity of the bus very much. Technically there is a change, but it's so very small and miniscule that it barely registers. To any casual observer not paying very close attention, they don't notice anything at all. So effectively the force on the firefly is a lot greater since the firefly got the worst end of the deal.
So in short, we look at the velocity of each object and see which velocity changed the most. In this case, the firefly's velocity changed from whatever speed it was flying to 0 when it stops flying all together. That's why the force is greater on the bug.
I can't tell because I can't see the picture but it seems like
