Choose a, b, c, or d to complete the following paragraph.
Tornadoes are vertical funnels of rapidly spinning air. …1… winds may top 250 miles (400 kilometers) an hour and can clear-cut a pathway a mile (1.6 kilometers) wide and 50 miles (80 kilometers long).
Twisters are born in thunderstorms and …2… often accompanied by hail. Giant, persistent thunderstorms called supercells spawn the most destructive tornadoes.
These violent storms occur around the world, …3… the United States is a major hotspot with about a thousand tornadoes every year. “Tornado Alley”, a region that includes eastern South Dakota, Nebraska, Kansas, Oklahoma, northern Texas, and eastern Colorado, is home to the most powerful and destructive of these …4…. U.S. tornadoes can cause 80 deaths and more than 1,500 injuries per year.
A tornado forms when changes in wind speed and direction create a horizontal spinning effect within a storm cell. This …5… is then tipped vertical by rising air moving up through the thunderclouds.