首页
登录
职称英语
About fifty years ago, plant physiologists set out to grow roots by themselv
About fifty years ago, plant physiologists set out to grow roots by themselv
游客
2025-02-02
9
管理
问题
About fifty years ago, plant physiologists set out to grow roots by themselves in solutions in laboratory flasks. The scientists found that the nutrition of isolated roots was quite simple. They required sugar and the usual minerals and vitamins. However, they did not require organic nitrogen compounds. These roots got along fine on mineral inorganic nitrogen. Roots are capable of making their own proteins and other organic compounds. These activities by roots require energy, of course. The process of respiration uses sugar to make the high energy compound ATP, which drives the biochemical reactions. Respiration also requires oxygen. Highly active roots require a good deal of oxygen.
The study of isolated roots has provided an understanding of the relationship between shoots and roots in intact plants. The leaves of the shoots provide the roots with sugar and vitamins, and the roots provide the shoots with water and minerals. In addition, roots can provide the shoots with organic nitrogen compounds. This comes in handy for the growth of buds in the early spring when leaves are not yet functioning. Once leaves begin photosynthesizing, they produce protein, but only mature leaves can "export" protein to the rest of the plant in the form of amino acids. [br] Which of the following best describes the organization of the passage?
选项
A、The results of two experiments are compared.
B、A generalization is made, and several examples of it are given.
C、The findings of an experiment are explained.
D、A hypothesis is presented, and several means of proving it are suggested.
答案
C
解析
主旨题型。第二段第一句为本文的主旨。而这是植物生理学家通过研究种植在实验瓶中的根,及在此基础上研究根、芽作为植物整体间的关系取得的:本文对此作了较详尽的解释。因此选项C为答案。
转载请注明原文地址:https://tihaiku.com/zcyy/3940110.html
相关试题推荐
Somepeopleprefertoworkforthemselvesorownabusiness.Othersprefertowo
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
随机试题
Thefirstwaywecanapproachlanguageisasaphenomenonoftheindividual
CongressmakesthelawsintheUnitedStates.Ithastwopans,whicharemor
Working-classfamiliesintheUnitedStatesareusuallynuclear,andmanyst
Peter,DavidandPaulsaidfollowingsentences:Peter:Davidisaliar,Paulal
吸收胆盐和维生素B12的部位是()A.胃 B.十二指肠 C.回肠 D.结
2016年公务员面试备考:专岗专训-党群机关职能及素质要求
下列哪项不是诊断小儿呼吸心跳骤停的依据A.心跳呼吸停止 B.颈动脉、股动脉波动
各种运输方式内外部的各个方面的构成和联系,就是( )。 A.运输系统
临时设施摊销费属于()。A.材料费 B.机械使用费 C.其他
发热的判断标准是指人体昼夜体温波动超过1℃,腋下温度超过A.36.7℃ B.3
最新回复
(
0
)