The formation of intense tornadoes requires the most powerful of all thunderstorms, called __________, that you can see here. These thunderstorms, which account for less than 10% of all thunderstorms, usually form in the United States during the spring, between the Rocky and Appalachian Mountains.
A) a vortex
B) cyclones
C) supercells
D) wall clouds

Respuesta :

B. Cyclones is the correct answer because super cells are clouds, as well as wall clouds, and a vortex is another, less powerful tornado.