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 strong 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 grea A. tiny plants and animals in the sea B. the grassy slopes of northern Canada C. their young in cold winter D. the abundant seafood in tropic waters [判断题] 钢的变形抗力随着加热温度的升高而增加。
A.正确 B.错误 [单项选择]男性,42岁,船工,会阴撞于船轮上,不能排尿,尿道口出血,不久出现阴茎、阴囊及下腹壁肿胀。导致迅速肿胀的原因,可能是()
A. 血肿 B. 血肿及尿外渗 C. 尿外渗 D. 水肿 E. 乳糜尿 [单选题]允许速度Vmax≤120km/h正线,轨道动态质量容许偏差管理值,高低(波长1.5~42m)I级偏差管理值为(???)mm。
A.5 B.7 C.8 D.12 [多项选择]继发性肺结核的好发部位包括
A. 上叶尖后段 B. 上叶前段 C. 下叶背段 D. 下叶基底段 [单选题]【单选题】 下列哪个选项属于对内的舆情引导流程。( ) (正确)
A.预警; B.快速反应; C.公开回应; D.善后修复 [判断题]汽车吊试验应遵守GB5905的规定,维护与保养应遵守ZNJ80001的规定。
A.正确 B.错误 [单选题]LKJ-2000监控装置显示界面的主窗口区位于中间,设有( )的显示框,显示测距仪的各种状态信息。
A.屏幕数据 B.各种数据 C.坡道数据 [单选题]变压器呼吸器中的硅胶在吸潮后,其颜色应为( )
A.粉红色; B.橘黄色; C.淡蓝色; D.深红色 我来回答: 提交
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