What do Yellowstone's geysers, hot springs, fumaroles, and mudpots all have in common?
A. They all blast thousands of gallons of superheated water and steam high into the air.
B. They are all hydrothermal features powered by an underground magma chamber.
C. They all erupt on a regular, predictable basis each and every day.
D. They all ooze hot, molten rock to the surface where it cools and hardens.