Fact 1: Cold fronts cause thunderstorms as they pass by. Fact 2: If cold air is advancing on warm air, the front is called a cold front. Given the two facts above, which situation can cause a thunderstorm?
OPTIONS:
a). Fog rising over a lake
b). pressure differences.
c). Earth's axis of rotation is tilted
d). Setting up lightning rods
e). Cold air advancing on cold air
f). Cold air advancing on warm air
g). Changing the angle of the sun
h). fall moving to winter
Answer:
f).