In most earthquakes the earth's crust cracks like porcelain. stress builds up until a fracture forms at a depth of a few kilometers and the crust slips to relieve the stress. some earthquakes, however, take place hundreds of kilometers down in the earth's mantle, where high pressure makes rock so ductile that it flows instead of cracking, even under stress severe enough to deform it like putty. how can there be earthquakes at such depths?
another positive effect of cultural diffusion is when new technologies are shared around the world. the spread of diseases is another negative effect of cultural diffusion. diseases such as aids , smallpox , and the bubonic plague have killed millions of people as they were spread from one are to another.
answer; ///i believe that the correct answer is the sailboat; ///ancient mesopotamia were the first people to ever invent and build sailboats.
the berlin blockade is known as the first event of the cold war, which was between the urss and the us without direct actions against each other. the blockade was a response to the monetary reform that invented a german mark and the soviets were against it, so they blocked all the routes to berlin without letting it have supplies. the answer is they did not want to use military force against the ussr, a big characteristic of the cold war.
try letter c. if that doesn't work, pick d