首页
登录
职称英语
Generally, in order to be preserved in the fossil record, organisms must
Generally, in order to be preserved in the fossil record, organisms must
游客
2025-02-09
24
管理
问题
Generally, in order to be preserved in the fossil record, organisms must possess hard body parts
such as shells or bones. Soft, fleshy structures are quickly destroyed by predators pr decayed by
bacteria. Even hard parts left on the surface for and length of time will be destroyed Therefore,
organisms must be buried rapidly to escape destruction by the elements and to be protected
(5) agents of weathering and erosion Marine organisms thus are better candidates for
fossilization than those living on the land because the ocean is typically the site of sedimentation,
whereas the land is largely the site of erosion.
The beds of ancient lakes were also excellent sites for rapid burial of skeletal remains of
freshwater organisms and skeletons of other animals, including those of early humans Ancient
(10) swamps were particularly plentiful with prolific growths of vegetation, which fossilized in
abundance. Many animals became trapped in bogs overgrown by vegetation. The environment of
the swamps kept bacterial decay to a minimum, which greatly (aide(D)in the preservation of plants
and animals. The rapidly accumulating sediments in flood plains, deltas, and stream channels
buried freshwater organisms, along with other plants and animals that happened to fall into the
(15) water.
Only a small fraction of all the organisms that have ever lived are preserved as fossils. Normally,
the remains of a plant or animal are completely destroyed through predation and decay. Although
it seems that fossilization is common for some organisms, for others it is almost impossible. For
the most part, the remains of organisms are recycled in the earth, which is fortunate because
(20) otherwise soil and water would soon become depieted of essential nutrients. Also, most of the
fossils exposed on Earth’s surface are destroyed by weathering processes. This makes for an
incomplete fossil record with poor or no representation of certain species.
The best fossils are those composed of unaltered remains. Generally, it is the inorganic hard parts,
composed mostly of calcium carbonate, that form the vast majority of unaltered fossils. Calcite and
(25) aragonite also contributed to a substantial number of fossils of certain organisms.
选项
A、is not likely to appear in the fossil record
B、is not heavy enough to sink below the surface
C、is not attractive to predators
D、takes a long time to decay
答案
A
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3949737.html
相关试题推荐
Generally,inordertobepreservedinthefossilrecord,organismsmust
Palcontologists(haveexamined)fossilembryosandhatchlings(from)three(type
(Fossil)recordssupporttheassumption(which)microorganisms(were)thefirst
(Amost)usefultool(foranalyzing)theelemental(compositionoffossils)ist
→Mammalsandbirdsgenerallymaintainbodytemperaturewithinanarrowrange
→Mammalsandbirdsgenerallymaintainbodytemperaturewithinanarrowrange
→Mammalsandbirdsgenerallymaintainbodytemperaturewithinanarrowrange
→Mammalsandbirdsgenerallymaintainbodytemperaturewithinanarrowrange
→Mammalsandbirdsgenerallymaintainbodytemperaturewithinanarrowrange
→Mammalsandbirdsgenerallymaintainbodytemperaturewithinanarrowrange
随机试题
MotivationforWordsMotivationdealswiththeconnectionbetween
"Shemustbeinthedormitorynow.""No,she______bethere.Isawherinthec
UNICEFisjoiningwithanonprofitgrouptobringAIDS【D1】______programsto
建筑施工安全检查标准》JGJ59-2011,宿舍内住宿人员人均面积不应小于2.5
关于免疫重建的叙述,下列哪项是正确的()A.输入同种异体淋巴细胞 B.胚胎
女性,56岁,1年前开始出现久站或咳嗽时左腹股沟区胀痛,平卧时无不适。查体:体态
汗证湿热迫蒸证,治疗原则是()A.益气固表 B.调和营卫 C.益气养阴
α-葡萄糖苷酶抑制剂降低血糖的作用机制是A.增加胰岛素分泌B.减少胰岛素清除C.
企业销售原材料取得的收入,比照商品销售的确认和计量原则进行处理。()
下列属于我国项目监理机构在施工阶段投资控制的主要工作的是( )。A.分析可能发
最新回复
(
0
)