Students who lived near a desert area in Saudi Arabia, were investigating the effects of river processes in a valley called a wadi. Although there was no river flowing in the valley when the students were doing their fieldwork, they could see some evidence of the work of the river when it had flowed through the valley. The students investigated the following hypotheses: Hypothesis 1: The gradient of the valley floor decreases downstream. Hypothesis 2: The river's bedload becomes smaller and more rounded downstream.

(a) Study Fig. 6, which shows the global distribution of areas with tropical rainforest and tropical desert climates....

Study Fig. 3, a climate graph for the city of Arica. Arica is in the Atacama Desert in Chile, South America. [Figure 3]

Study Photograph A (Insert), of a river and its surroundings, and Fig. 6, which is a field sketch of the same area. [...

Study the 1:25000 map of Curepipe, Mauritius.

Study Photograph A (Insert), which shows part of the CBD of Zimbabwe's capital city, Harare, and Fig. 3, a sketch of ...

Study Fig. 4, which shows the percentage of population living in urban areas and GDP per person (a measure of wealth)...