1 .		Downdrafts are aided by the influx of cool, dry air surrounding the cloud during a process called entrainment.   True  False
2 .		More tornadoes occur in the central United States than any other part of the world.   True  False
3 .		The greatest number of weather-related deaths occurs from flash floods.   True  False
4 .		A vast majority (80% or more) of the moisture that condenses in an air-mass thunderstorm leaves the cloud as precipitation.   True  False
5 .		The greatest number of air-mass thunderstorms occur in the Plains states.   True  False
6 .		A tornado warning is issued by local offices of the National Weather Service when a tornado has actually been sighted in an area or is indicated by weather radar.   True  False
7 .		The average tornado travels across the land at approximately 45 kilometers (30 miles) per hour.   True  False
8 .		In the midlatitudes, lightning is seldom observed in the winter.   True  False
9 .		Over 90% of all mesocyclones produce tornadoes.   True  False
10 .		The probability of a tornado striking a given point in the region most frequently subject to tornadoes is about one in 25 years.   True  False
11 .		The least common but more dangerous type of lightning is sheet lightning.   True  False