Describe chemically formed sedimentary rocks under the following headings;
(a) mode of formation (b) examples (c) importance.

Explain the occurrence of drought under the following headings:
(a) causes (b) area affected (c) effects (d) control

(a) List three processes of river erosion

(b) Outline four characteristics of each of the following sections of a river valley: (i) upper course (ii) middle course (iii) lower course.