An ice age is a period of long-term reduction in the temperature of the Earth's surface and atmosphere,resulting in an expansion of continental ice sheets,polar ice sheets and alpine glaciers.Glaciologically,ice age is often used to mean a period of ice sheets in the northern and southern hemispheres.More colloquially,when speaking of the last few million years,ice age is used to refer to colder periods with extensive ice sheets over the North American and Eurasian continents:in this sense,the most recent ice age peaked about 11,000 years ago.
最新问答: (2009•张家界二模)下列关于生物圈的说法中,正确的是( ) 有两台功率大小不同的起重机,已知它们的功率之比为1:3若让它们完成的功相同,则所用时间之比为多少? 如何去除水中的氯化亚铁和硫酸亚铁 紫色石蕊试液遇二氧化碳变红的化学方程式 下列哪一生态系统被誉为“地球之肺”( ) A.湿地生态系统 B.草原生态系统 C.森林生态系统 D.湖泊生态系统 we had strong wind and heavy rain last night.改为同义句 哪位大哥知道光速的准确数值?要9位有效数字 the doctor told him not to smoke ,but he did ____the opposit 七年级英语寒假乐园人教新目标版上的一道题 碳酸钙的化合价是多少 用 as if 造2个句子~(用 as if 最常见的两种用法造2个不同的句子, 你两天前去农场了吗?用英语怎么说 一块长方形草坪的周长是36米,已知长是宽的2倍,这块长方形草坪的面积是多少平方米?列方程解答. 某同学在折千纸鹤,如果每小时折5个,就可以在预定时间内完成,当折好10后,效率提高60%,因而不但提前3小时完成,还多折 锡被氧原子氧化,是放热反应还是吸热反应? 看见荒山、欢笑这些词,你联想到了哪些成语? 惰、轮、液、稚、碍、讳的形近字组词 高中英语完形中的一道题 部分原文:As a parent,you should also be ready to act y=2x+ 根号(1-x^2)不要用三角函数!求值域 好奇.造句.
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