Why does semi arid climate exist?

Which lake is located on the southern fringe of the Sahara desert? Is lake Ontario dangerous? What war was over sailing rights in the mediterranean sea? How has the Nile rivers course changed over time? The Mississippi River would be open for trade to both the Americans and the British according to what? What is the most southern sea called? What year did the eurasian ruffe first arrive in great lake? This is found on beaches of West Coast the beaches often looks black because of it starting with I? Flow regime refers to? What is the deepest area of a large lake? How many lakes are in Missouri? What are examples of analogies in lake? Does the nile river flow through the pyramids of Giza? Can you show me a picture of Mount McKinley? When is it most likely for a river to become a stagnant? Where the tourist can stay while visiting dhabil darwaza? List of rivers in the southwest region? When was the Atacama Desert built and where? What time does knotts scary farm open? Witch country is the Amazon rainforest in?