Please help What differentiates one layer of the atmosphere from one another?

Please help

The stratosphere and the troposphere are defined by the variation in temperature with height. Within a troposphere, the temperature drops as altitude increases, and drops fast enough for convection to occur. Whereas within a stratosphere, the temperature rises with increasing altitude. Features of the atmosphere change with altitude: density decreases, air pressure decreases, temperature changes vary. Different temperature gradients create different layers within the atmosphere. The lowest layer is the troposphere where most of the atmospheric gases and all of the planet's weather are located.

Explanation:

graph slopes whilst gas cools, then it is flat whilst conensation to liquid happens, the coolong liquid then graphs as a slope when it solidifies graph is flat

latent heat

the answer is f1 and d2 because if you put equal force on those two points the beam would balance trust me on this