Plants can’t communicate by moving or ma

题型:阅读理解

问题:

Plants can’t communicate by moving or making sounds, as most animals do. Instead, plants Produce volatile compounds, chemicals that easily change from a liquid to a gas. A flower’s sweet smell, for example, comes from volatile compounds that the plant produces to attract insects such as Bugs and bees.

Plants can also detect volatile compounds produced by other plants. A tree under attack by Hungry insets, for instance, may give off volatile compounds that let other trees know about the Attack. In response, the other trees may send off chemicals to keep the bugs away ——or even  Chemicals that attract the bugs’ natural enemies.

Now scientists have created a quick way to understand what plants are saying: a chemical Sensor(传感器)called an electronic nose. The “e-nose” can tell compounds that crop plants make When they’re attacked Scientists say the e-nose could help quickly detect whether plants are being Eaten by insects. But today the only way to detect such insects is to visually inspect individual Plants. This is a challenging task for managers of greenhouses, enclosed gardens than can house Thousands of plants.

The research team worked with an e-nose than recognizes volatile compounds. Inside the device, 13 sensors chemically react with volatile compounds Based on these interactions, the e-nose gives off electronic signals that the scientists analyze using computer software.

To test the nose, the team presented it with healthy leaves from cucumber, pepper and tomato plants, all common greenhouse crops. Then scientists collected samples of air around damaged leaves from each type of crop, These plants had been damaged by insects, or by scientists who made holes in the leaves with a hole punch(打孔器). The e-nose, it turns out, could identify healthy cucumber, pepper and tomato plants based on The volatile compounds they produce, It could also identify tomato leaves that had been damaged. But even more impressive, the device could tell which type of damage ---- by insects or with a hole Punch ---- had been done to the tomato leaves.

With some fine-tuning, a device like the e-nose could one day be used in greenhouses to quickly spot harmful bugs, the researchers say. A device like this could also be used to identify fruits that are perfectly ripe and ready to pick and eat, says Natalia Dudareva, a biochemist at Purdue University in West Lafayette, Ind. who studies smells of flowers and plants. Hopefully, scientists believe, the device could bring large benefits to greenhouse managers in the near future.

小题1:We learn from the text that plants communicate with each other by____.

A.making some sounds

B.waving their leaves

C.producing some chemicals

D.sending out electronic signals小题2:What did the scientists do to find out if the e-nose worked?

A.They presented it with all common crops.

B.They fixed 13 sensors inside the device.

C.They collected different damaged leaves.

D.They made tests on damaged and healthy leaves.小题3:According to the writer, the most amazing thing about the e-nose is that it can___.

A.pick out ripe fruits

B.spot the insects quickly

C.distinguish different damages to the leaves

D.recognize unhealthy tomato leaves小题4:We can infer from the last paragraph that the e-nose_____.

A.is unable to tell the smell of flowers

B.is not yet used in greenhouses

C.is designed by scientists at Purdue

D.is helpful in killing harmful insects

考点:社会现象类阅读
题型:阅读理解

《中华人民共和国未成年人保护法》规定,“任何人不得在中小学、幼儿园、托儿所的教室、寝室、活动室或其他未成年人集体活动的室内吸烟”,这是为了保护学生的()。

A.人身自由权

B.身心健康权

C.人格尊严权

D.隐私权

题型:阅读理解

在随机接入响应中,如果相应的随机接入响应的频率跳变字段设置为()UE将执行PUSCH频率跳变。

A.0

B.1

C.2

D.6

题型:阅读理解

以下程序中,错误的行为
  ① # include <iostream.h>
  ②class A
  ③
  ④ public:
  ⑤  int n=2;
  ⑥  A(int val) cout < < val < < endl;
  ⑦  ~A( ) ;
  ⑧ ;
  ⑨void main( )
  ⑩
  ⑾ A a(0);
  ⑿

A.⑤

B.⑥

C.⑦

D.⑾

题型:阅读理解

关于建立邮件列表的说法错误的是()。

A、邮件列表的建立通常与网站的其他功能分开,由一个人或一个部门独立完成,杜绝其他干扰

B、一个高质量的邮件列表是企业增强竞争优势的重要手段之一

C、邮件列表的用户数量需要较长时期的积累,为了获得更多的用户,还需要对邮件列表本身进行必要的推广,需要投入相当的营销资源

D、邮件列表必须是用户自愿加入的,要能够长期保持用户的稳定增加,邮件列表的内容必须对用户有价值,邮件内容也需要专业的制作

题型:阅读理解

一般而言,一个较高抽象层次的计算系统是可以这样实现的,即()

A.将较低抽象层次的重复性组合,命名为较高抽象层次的指令

B.利用较高抽象层次的指令进行复合、抽象与构造,即形成高抽象层次的程序

C.高抽象层次的程序通过其程序执行机构解释为高抽象层次的指令及其操作次序。高抽象层次的指令被替换为低抽象层次的程序,再由低抽象层次的程序执行机构解释并执行

D.上述A-C全部

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