Question

What is biotic process of deserts

Answer 1

Any one

Answer 2

The formation of the subtropical high-pressure cell.
The rain shadow effect in the belt of easterly trade winds.
The effect of the cold currents off the west coast of the continents at these latitudes.
The depositing sands of a desert along its border into the fertile land

Answer 3

Aright, so a biotic part of an ecosystem is the living part and a process is "The actions or events that link organisms, including humans, and their environment, including production, decay, nutrient cycling, disturbance and successional development" (dictionary definition).

So what living processes do you think occur within a desert? :)