The weathered debris in deserts consists mainly of a. a thick soil layer b. organic material from decaying plants c. unchanged rock and mineral fragments d. chemically altered rock fragments

Answer;

C. unchanged rock and mineral fragments

Explanation;

A large number of landforms and features found in desert environments are formed as the result of weathering. Weathering is defined as the breakdown and deposition of rocks by weather acting in situ

The two main types of weathering which occur in deserts are Mechanical weathering, which is the disintegration of a rock by mechanical forces that do not change the rock's chemical composition and Chemical weathering, which is the decomposition of a rock by the alteration of its chemical composition.

By contrast much of the weathered debris in deserts has resulted from mechanical weathering. Chemical weathering, however, is not completely absent in deserts. Over long time spans,clays and thin soils do form.

if you mean hydrogen and oxygen then water is the product