“Snow and ice, often more than 2 miles (3 km) thick, constantly cover the surfaces of —- regions. Lichens are the only form of vegetation that can survive in these areas where monthly temperatures average below freezing.”

“Snow and ice, often more than 2 miles (3 km) thick, constantly cover the surfaces of —- regions. Lichens are the only form of vegetation that can survive in these areas where monthly temperatures average below freezing.”

Ice cap