A- Leaf 1
B - Leaf 2
C - leaf 3
D - leaf 4

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.

i don't see a text, but i am gonna assume this *orbit* the curved path, usually elliptical, described by a planet, satellite, spaceship, etc., around a celestial body, as the sun.