Why does semi arid climate exist?

Which nation had coastlines on the north sea? What aquariums have killer whales? What challenges did michelangelo face when painting the Sistine Chapel? did rocky bleier have surgery? Plant and animal adaptations in the Atlantic ocean? What is a company who dumps chemicals into a river called? Is warwick castle a good model of defence? When should you cut down a Christmas tree? Did Melophites create the coliseum? What is lake Victoria boraderd by? The ocean of Cancun is that on the pacific or Atlantic ocean? What are the mill rates for Kelowna? What are the mineral resources in the Pacific Ocean? What is length of alimentry canal? Were is surtsey island located? Tributaries of the Nidd? If the Atlantic ocean is the second deepest ocean what is the deepest ocean? What language is canyon borrowed from? What form of transportation replaced the canals? What sea is north of the black sea?