article: People sometimes say, "It's raining cats and dogs!" when there is a heavy rain. Nobody has ever really seen cats and dogs falling from the sky, but there have been many reports of other strange things "raining" down. In 1956, the people of a town in the USA saw a small black cloud in the sky. It started to rain from the cloud normally, but only in a small area. The cloud then turned white, and fish started to fall to the ground. Most of them were still alive.
  During a storm in July 1901, in Minneapolis, people heard something falling from the sky that did not sound like rain. When they went outside, they found all types of frogs covering four streets.
  There are other reports of strange "rains" failing from the sky including worms, insects and snakes.
  Can these strange "rains" be explained by science? Scientists usually say that a tornado   has picked up the animals from a river or ocean, carried them for miles, and then dropped them somewhere else. But this does not completely explain all of them. On May 15, 1890, in Italy, there was a rain of birds' blood. Scientists said that flying birds must have been torn   to pieces by strong winds. But if so, why did only their blood fall from the sky , and not other parts of their bodies? And anyway, there were no strong winds that day!
question: According to scientists, what can move things from the ground to the sky?
options: Storms. Rains. Clouds. Tornadoes.