The Southern Oscillation
A) occurs independently of El Nio.
B) occurs only during La Nia events.
C) is linked to changes in atmospheric pressure over the western Pacific and eastern Indian Oceans.
D) has not occurred for several decades.
E) is also called the Arctic Oscillation.
Question 2
Over the past half century, El Nio events occurred about every ____ years, on average.
A) 2
B) 5
C) 8
D) 10
E) 25