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