Just beneath the surface of Yellowstone National Park is a large ________.
A) karst cavern
B) aquifer
C) volcano
D) magma chamber
E) area of tower karst
Question 2
Old Faithful is now less predictable because of ________.
A) earthquakes in the 1980s
B) lessening rainfall because of climate change
C) human changes to the landscape around the geyser
D) cooling of Yellowstone's underground magma chamber
E) the natural damming of the Firehole River