Why do scientists believe the polar ice is disappearing?


water pollution


global warming


garbage dumping


polar bears are breaking it up

What are the main causes of global warming?


emissions from cars and factories


discharge from water treatment plants


chemicals in the water


hazardous waste buried underground


How do polar bears use ice?


drinking water


food


means of travel


platform for hunting seals

What is one human activity that may be contributing most to melting of the ice?


dumping chemicals in water


driving cars


speeding up soil erosion


mining gold and silver