the eastern and western deserts prevented invaders from the east and west. The deserts were a hard climate to travel through. Therefore, nobody could walk across to conquer Egypt. Furthermore, the cataracts in the Nile to the south protected the Egyptians from lands below them.
The correct answer is - Their livelihoods are derived from the land.
People in Sub-Saharan Africa are predominantly working in agriculture. They produce most of their food, so their well being is heavily influenced by what they can produce. When an environmental issue occurs, it causes lots of problems, but most importantly hunger. They are producing vegetables, crops and fruits in a primitive manner, are not financially capable to protect their plants, so any major environmental issue is a catastrophe for them. <span />
Its an indirect presedent election.