首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
考研
Perhaps the most familiar plant movement belongs to one species of mimosa called the sensitive plant. Within seconds, it can low
Perhaps the most familiar plant movement belongs to one species of mimosa called the sensitive plant. Within seconds, it can low
admin
2011-01-17
51
问题
Perhaps the most familiar plant movement belongs to one species of mimosa called the sensitive plant. Within seconds, it can lower its leaves and make its tiny leaflets close up like folding chairs. This movement is thought to be initiated by electrical impulses remarkably similar to nerve signals in animals. But without the animals’ sophisticated motion machinery, the mimosa has had to be creative in devising a way to move.
For motion, the plant depends on tiny, bulb-shaped organs located at the base of each leaf stalk and leaflet. Called pulvini, these organs hold the plant parts in place. When the mimosa is stimulated--say, by a crawling insect or a sudden change in temperature--an electrical impulse sweeps through the plant. This causes potassium and then water to be shifted from certain cells in the pulvini to others, quickly turning one side of the organs flaccid. Because the pulvini can no longer support the leaves and leaflets, this shift results in a corresponding change in their position.
According to the passage, what causes potassium and water in the mimosa to shift from some cells to others?
选项
A、Signals from the pulvini.
B、Movements of the leaf stalks.
C、Electrical impulses.
D、Nerve signals.
答案
C
解析
第二段第四句This causes potassium... 中的This指的正是上句中的electrical impulses。
转载请注明原文地址:https://kaotiyun.com/show/uSYi777K
本试题收录于:
GCT工程硕士(英语)题库专业硕士分类
0
GCT工程硕士(英语)
专业硕士
相关试题推荐
Accordingtothespeaker,theproblemwith"insidervolumes"isthatthey______.Whenthespeakersaysthathesimultaneously
Accordingtothespeaker,theproblemwith"insidervolumes"isthatthey______.Whenthespeakersaysthathe"putthatproje
Theproblemwiththereadingcourseasmentionedinthefirstparagraphisthat______.Accordingtothepassage,learningtor
Thepassagefocuseson______.Inthesecondparagraphtheword"paramagnetic"means______.
Somepsychologistsmaintainthatthinkingis______.Accordingtotheselection,muscleparticipationintheprocessofthinkin
Thepassageismainlyconcernedwiththe______.Accordingtothepassage,whatcausespotassiumandwaterinthemimosatoshi
Thepassageismainlyconcernedwiththe______.Itcanbeinferredfromthepassagethatthemimosaiscalledthesensitivepl
Thenextdecadecouldseecommutersspeedingtoworkatabout300milesperhouraboardmagneticlevitationvehicles,according
Thereweremanypeoplepresentandheappearedonlyforafewseconds,soIonlycaughta______ofhim.
随机试题
A物品价格从7元上升为9元,这就引起供给量从4500单位增加到5500单位。该物品的供给弹性是()
肛门检查了解内容下列哪项应除外
以下关于同步电动机的正确论述为()。
增值税一般纳税人取得的增值税专用发票,可以作为抵扣凭证的是( )。
根据企业所得税法律制度的规定,下列各项中,属于特许权使用费收入的是()。
邓小平提出“发展才是硬道理”的著名论断是在()。
严复的文化教育观可以概括为()。
根据汉字国标GB2312—80的规定,一个汉字的内码码长为_______。
Itwasrecommendedthatpassengers_______smokeduringtheflight.
A、Theydon’tdamagecomputersystems.B、Theyneedtoattachthemselvestootherfiles.C、Theycouldspreadontheirownthrough
最新回复
(
0
)