Why most of the the worlds deserts are located in western margins of continentsin the subtropics

Question

Why most of the the worlds deserts are located in western margins of continentsin the subtropics

Answer 1

Deserts landscapes are more diverse than many expect. Some are found on a flat shield of ancient crystalline rocks hardened over many millions of years, yielding flat deserts of rock and sand such as the Sahara. Others are the folded product of more recent tectonic movements, and have evolved into crumpled landscapes of rocky mountains emerging from lowland sedimentary plains, as in Central Asia or North America .

Answer 2

Because water runs down hill, and since the eastern margins are lower than the western margins, the water run to the east from the west, and the lack of water creates deserts.

Answer 3

I think it is to do with earths rotation which is from west to east. Winds carrying moisture and rainfall are influenced by this and travel in opposite direction and dry up by the time they reach the other side of the continent.