问题
选择题
| 下列说法中正确的是（ ） A．两个分子间的距离越大，分子势能越小 B．物体温升高1℃，也可以说是升高了1K C．能量耗散现象说明自然界的总能量是逐渐减少的 D．由于自然界的总能量是守恒的，所以不需要节约能源 |
答案
答案：B
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| 下列说法中正确的是（ ） A．两个分子间的距离越大，分子势能越小 B．物体温升高1℃，也可以说是升高了1K C．能量耗散现象说明自然界的总能量是逐渐减少的 D．由于自然界的总能量是守恒的，所以不需要节约能源 |
答案：B
| Some people associate migration mainly with birds. Birds do travel vast distances, but mammals also migrate. An example is the caribou, reindeer that graze on the grassy slopes of northern Canada. When the weather turns cold, they travel south until spring. Their tracks are so well-worn that they are clearly visible from the air. Another migrating mammal is the Alaska fur seal. These seals breed only in the Pribilot Islands in the Bering Sea. The young are born in June and by September are p enough to go with their mothers on a journey of over 3,000 miles. Together they swim down the Pacific Coast of North America. The females and young travel as far as southern California. The males do not journey so far. They swim only to the Gulf of Alaska. In the spring, males and females all return to the islands, and there the cycle begins again. Whales are among the greatest migrators of all. The humpback and blue whales migrate thousands of miles each year from the polar seas to the tropics. Whales eat huge quantities of plankton. These are most abundant in cold polar waters. In winter, the whales move to warm waters to breed and give birth to their young. |
From the passage we can learn that ______.
A．people migrate like animals
B．only birds migrate
C．the female fur seals migrate only to the Gulf of Alaska
D．not all mammals migrate