Choose the number of the sentence that expresses the main idea in each selection. Then click on "GO." Question5. (1) Polar bears are excellent swimmers. (2) They slip through the water at speeds up to six miles an hour, using their front legs to move them forward. (3) With their nostrils closed and their eyes open, then can also dive underwater, staying there for as long as two minutes. (4) When they emerge, they immediately shake the water off their fur before the water freezes. (5) Polar bears are equally able to move well over the icy landscape. (6) On very smooth, slippery slopes, a polar bear may move by sliding on its belly. (7) With its legs stretched outward, it will descend in a spray of powdery snow. (8) When walking over ice, the polar bear walks bow-legged with toes inward. (9) This posture enables the huge animal to move along without slipping. (10) Clearly, the polar bear is very skillful at moving around its watery and icy environment