a huge, moving mass of ice
wearing away of the Earth's surface by water, or wind
a flat, sandy area where a river enters an ocean
a high, flat landform
a way to draw the curved areas of the Earth on a flat surface
related to regions near the equator; a tropical climate is very warm and moist
coal, oil, or natural gas that formed over millions of years from the remains of plants and tiny animals
a resource that can be replaced as it is used
a resource that cannot be replaced by natural resources or is replaced extremely slowly
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