The downdraft in an ordinary cell thunderstorm is created mainly by ____.
A) the melting of snow in the anvil
B) electrical attraction between the cloud and ground
C) the release of latent heat as water in the cloud freezes
D) evaporating raindrops that make the air cold and heavy
Question 2
Pollution is most severe in urban areas when a ____.
A) cold upper-level low moves into a region
B) cold front passes through the area
C) large slow-moving anticyclone moves into an area
D) storm system begins developing to the west
