Much of botswana and namibia is covered by that can support few people.

Much of Botswana and Namibia is covered by desert that can support few people. Botswana's climatic pattern is typical of southern Africa, although its rainfall is less than countries further east. As with Namibia, temperatures increase by about 6 degrees for every 100 m you descend. As a result, Namibia's park is hotter, especially those located in the desert. Rainfall is higher in the far North, including Etosha, and the Zambezi Region. Further south the climate is hotter and drier. 

What have scientists learned about plant behavior by studying the dodder plant

  like australopithecus afarensis; probably the direct ancestor of this group. africa: 5.8 to 4.4 million years ago.