High-Q | English פסיכומטרי

Reading Comprehension

In past ages they expanded greatly over the land. Four times in the Pleistocene era, 5 extending roughly from one million years ago to ten thousand years ago, thick, moving ice sheets covered large parts of North America, Europe, and Asia. The icecaps of Antarctica and Greenland represent comparatively small remnants of two of the vast formations that covered 30% of the land in the last ice age. 10 that falls each winter fails to melt during the next summer. This happens in places where the average temperature in the summer months is near or below freezing. New snow falls on top of the residue from the previous year and vast snow fields are formed. The total snow cover becomes thicker, year by year, until the lower layers are transformed into ice. This is the area of accumulation. 15 When the snow field in the area of accumulation has reached a certain critical thickness (approximately 60 meters), a huge mass of ice and snow begins to move downhill or to spread outward. A glacier has been formed. Its forward progress will continue as long as enough snow accumulates on the snow field from which it is derived. At last its spreading edge will reach a place where the temperatures in summer average 20 well above the freezing point. In this area all of the past winter's snowfall will melt or evaporate during the summer. Some of the creeping ice beneath it will also melt, so that the ice mass becomes thinner and thinner as it flows. This is the area of dissipation. A glacier can maintain itself in a given place only as long as the supply of ice from colder areas equals the total of melting and evaporation. 25 Glaciers form because in various high mountains and plateaus some of the snow

41. It can be inferred from the

42. The phrase "this area" in line 2 refers to - (1) Greenland only (2) Greenland and Antarctica (3) land covered by glaciers (4) mountains with glaciers 43. The primary purpose of the third paragraph (lines 10-15) is - (1) to explain where glaciers are likely to be found (2) to describe how glaciers are created (3) to describe the effect of climate changes on glaciers (4) to show how glaciers change over time

information in the passage about glaciers that - (1) during the Pleistocene era, Greenland was at times entirely free of ice (2) no glaciers existed until the beginning of the Pleistocene era (3) the glaciers in North America

during the Pleistocene era were more extensive than those in Europe and Asia

(4) at some time in the past, the Earth's icecaps were about three times their present size

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