(1) Glaciers are created as many layers of snow and ice are compacted, or squeezed together. (2) With each new snowfall, the layers of snow become heavy and are gradually compressed into a very dense ice. (3) When enough mass has accumulated, the glacier will start to move, like a slow-flowing river, across the land. (4) In order for glaciers to form, the climate must be cold and snowy in the winter and fairly cool in the summer. (5) Around 75% of the Earth's fresh water is in these glaciers. (6) Today, they cover about 10% of the Earth's land area. (7) At the close of the last Ice Age, 10,000 years ago, almost a third of the surface of the Earth was covered by glacial ice.Which sentence provides evidence that best supports the main idea of the paragraph? A. Crevasses are deep cracks or chasms that can form in glacial ice. B. Glaciers will not form if the climate or water is overly warm. C. A glacier is a huge, slow-moving mass of compact snow and ice. D. Most glaciers are slowly receding due to recent climate changes.
