Fossils are the remains and traces of ancient plant and animal lives that are more than 10,000 years old. They range in size from microscopic structures to dinosaur skeletons and complete bodies of enormous animals. Skeletons of extinct species of human are also considered fossils.
An environment favorable to the growth and later preservation of organisms is required for the occurrence of fossils. Two conditions are almost always present: The possession of hard parts, either internal or external, such as bones, teeth, scales, shells, and wood; these parts remain after the rest of the organism has decayed. Organisms that lack hard parts, such as worms and jelly fish have left a meager geologic record. Quick burial of the dead organism, so that protection is afforded against weathering, bacterial action, and scavengers.
Nature provides many situations in which the remains of animals and plants are protected against destruction. Of these, marine sediment is by far th
A. quick burial.
B. cold storage.
C. quick temperature change.
D. lack of water
2015年中央经济工作会议指出，“推进供给侧结构性改革，是适应和引领经济发展新常态的重大创新。”供给侧改革，就是从供给、生产端入手，通过解放生产力，提升竞争力促进经济发展。下列选项符合供给侧改革的是（）
①增加财政支出，加大固定资产投资，拉动经济增长
②激活生产要素，提高生产效率，激发经济发展动力
③增加政府补贴，刺激消费需求，驱动经济增长
④通过减税，降低实体经济企业的成本，提升竞争力
| With only about 1,000 pandas left in
the world, China is desperately trying to clone the animal and save the
endangered species. That’s a move similar to what a Texas A&M University
researcher has been undertaking for the past five years in a project called
"Noah’s Ark." Dr. Duane Kraemer, a professor in Texas A&M’s College of Veterinary Medicine and a pioneer in embryo(胚胎) transfer work and related procedures, says he salutes the Chinese effort and "I wish them all the best success possible. It’s a worthwhile project, certainly not an easy one, and it’s very much like what we’re attempting here at Texas A&M--to save animals from extinction." Noah’s Ark is aimed at collecting eggs, embryos, semen (精子) and DNA of endangered animals and storing them in liquid nitrogen. If certain species should be come extinct, Kraeme A. Lack of available panda eggs. B. Lack of host animals. C. Lack of qualified researchers. D. Lack of funds. [单选题]电气火灾的引发是由于危险温度的存在,危险温度的引发主要是由于（ ）。
A.设备负载轻 B.电压波动 C.电流过大 [单项选择]其选方
A. 解语丹 B. 知柏地黄丸 C. 补阳还五汤 D. 涤痰汤 E. 左归丸 [判断题]曳引电梯，是靠曳引绳和轮绳槽之间的摩擦力来驱动轿厢移动的。
A.正确 B.错误 [判断题]遇天气恶劣，信号机显示距离不足400m时，司机或车站值班员须立即报告列车调度员，列车调度员应及时发布调度命令，改按天气恶劣难以辨认信号的办法行车。
A.正确 B.错误 [单选题]54)下列表述正确的是？
A.进线备自投是明备用方式； B.进线备自投是暗备用方式； C.桥备自投是明备用方式； D.以上均不正确 [多选题] 数字移动通信系统核心网的GSM−R核心网由( )等组成。(
A.移动交换子系统(SSS) B.移动智能网子系统(IN) C.通用分组无线业务子系统(GPRS)设备 D.分组域数据传输接口设备 我来回答: 提交
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