Read the following materials and answer the following questions. Material 1: The Great Rift Valley in East Africa is the longest rift zone on earth, and many lakes and materials are formed in the depths of the rift. (1) Internal force and external force * * * together constitute the surface morphology of the earth. The cliff on the bank of Lake Tanganyika stands due to internal forces, and the rock strata break off, and then it is eroded into the present landform by running water.

(2) Judging the terrain according to the altitude. In the picture, the altitude of the East African Plateau is relatively high, and most areas are above 1000m, with sparse contour lines in the middle and dense contour lines at the edges. The contour value decreases from the inside out.

(3) The natural conditions required for agricultural development include topography, climate, soil and water resources. From these aspects, the advantages of coffee production in the three countries are: low latitude, high temperature and sufficient heat; Tropical savanna climate, sunny; Terrain is plateau, with large temperature difference between day and night; The soil is fertile.

So the answer is:

(1) Under the action of internal force, the rock stratum breaks and collapses; Be eroded by running water

(2) Plateau (or East African Plateau), with high altitude, most areas are above 1000m, with sparse contour lines in the middle and dense contour lines at the edges; The contour value decreases from the inside out.

(3) Low latitude, high temperature and sufficient heat; Tropical savanna climate, sunny; Terrain is plateau, with large temperature difference between day and night; The soil is fertile.