In the Earth's atmosphere, why does pressure decrease exponentially with height?

Question

In the Earth's atmosphere, why does pressure decrease exponentially with height?

Answer 1

The higher you go, the less atmosphere is sitting on top of you.  Even atmosphere has weight, and we measure it as pressure.

Answer 2

Because it is in hydrostatic equilibrium.

Basically gravity and force due to gas pressure balance.

In the lower atmosphere, the gas has to have a high enough pressure to hold the weight of the overlying gas above it. As you move up through the atmosphere, there's less weight above pushing down, to the pressure doesn't need to be so high to maintain balance