单词：diel vertical migration
单词：diel vertical migration 相关文章
Oil Wealth Attracts Businesses to North Dakota 石油财富吸引企业进驻北达科他州 WILLISTON, NORTH DAKOTA The state of North Dakota has one of the lowest unemployment rates in the country, thanks to a glut of jobs created by the oil boom i
VOA标准英语2014年(八月)
This mother bear's experience gives her family a good chance of survival until spring arrives. They will return again and again as the thaw releases more fish. On the warmer plains and valleys that surround the plateau, grazers are on the move. They
自然百科2012年
Hot water scorches and drowns the roots of trees encroaching on the valleys. It can keep the forests in check and the rich pastures / open. Those pastures now produce the new grass needed to make rich milk and feed a bison baby boom. The few calves b
自然百科2012年
石油财富吸引企业进驻北达科他州 The state of North Dakota has one of the lowest unemployment rates in the country, thanks to a glut of jobs created by the oil boom in the western part of the state, which rests on one of the largest shal
VOA双语新闻 2014年8月
But that pales into insignificance, when compared to the daily vertical migration of these mircoscopic animals called zooplankton. At sunset, all of these tiny creatures swin upwards, and under cover of darkness, they grease on floating algae close t
自然百科2014年
Imagine if the only way for you to eat were to trek twenty-five miles on foot to a restaurant and then trek all the way back home afterwards. Imagine that this restaurant is a buffet, so you can't carry anything home in a doggie bag--you carry only w
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