Final answer:
The Great Rift Valley is a geological depression in Eastern Africa formed by the divergent tectonic movement creating the Western and Eastern Rifts with distinct geographical and ecological features.
Step-by-step explanation:
A geological depression that is caused by the triple junction apart of the Great Rift Valley is a valley created by the moving apart of tectonic plates. This rift can be found in Eastern Africa, extending from Mozambique to the Red Sea and includes features such as a series of deep water lakes that run along the Western Rift, highland ranges like the Rwenzori Mountains, and significant fossil finds like the skeleton of the hominid "Lucy." The Eastern Rift and Western Rift are distinct divisions, with the former experiencing active volcanism and varying climate areas including savannas and deserts due to the influence of surrounding highlands.