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ice sheet - n. a very large and thick area of ice that covers a region
pace - n. the speed at which someone or something moves
frequency - n. the number of times that something happens during a particular period
global - adj. involving the entire world
El Niño - n. a flow of unusually warm water along the western coast of South America that causes many changes in weather in other places (such as a lot of rain in areas that are usually dry)
