题干

将带有芽眼的马铃薯块茎切割后,埋在地里进行繁殖,这种繁殖方法属于(  )

A:孢子生殖

B:分裂生殖

C:有性生殖

D:无性生殖

上一题 下一题 0.0难度 选择题 更新时间:2017-10-17 12:02:47

答案(点此获取答案解析)

D

同类题3

能源、环境与人类生活和社会发展密切相关,研究它们的综合利用有重要意义.

(1)氧化还原法消除氮氧化物的转化如下:NO  NO2 N2

①反应I为:NO+O3=NO2+O2,生成11.2L O2(标准状况)时,转移电子的物质的量是____ mol.

②反应II中,当n(NO2):nCO(NH2)2=3:2时,反应的化学方程式是____  .

(2)硝化法是一种古老的生产硫酸的方法,同时实现氮氧化物的循环转化,主要反应为:

NO2(g)+SO2(g)⇌SO3(g)+NO(g)△H=﹣41.8kJ•mol﹣1

已知:2SO2(g)+O2(g)⇌2SO3(g)△H=﹣196.6kJ•mol﹣1.

写出NO和O2反应生成NO2的热化学方程式____ .

(3)将燃煤废气中的CO2转化为二甲醚的反应原理为:2CO2(g)+6H2(g) CH3OCH3(g)+3H2O(g);该反应平衡常数表达式为K= ____ .

(4)合成气CO和H2在一定条件下能发生如下反应:CO(g)+2H2(g)⇌CH3OH(g)△H<0.

在容积均为V L的I、Ⅱ、Ⅲ三个相同密闭容器中分别充入a mol CO和2a mol H2,三个容器的反应温度分别为T1、T2、T3且恒定不变,在其他条件相同的情况下,实验测得反应均进行到t min时CO的体积分数υ(CO)%如右图所示,此时I、Ⅱ、Ⅲ三个容器中一定达到化学平衡状态的是____ ;若三个容器内的反应再经过一段时间后都达到化学平衡时,CO转化率最大的反应温度是____ .

(5)据报道以二氧化碳为原料,采用特殊的电极电解强酸性的二氧化碳水溶液可得到多种燃料,其原理如图所示.电解时,b极上生成乙烯的电极反应式为____ .

同类题4

任务型阅读

    Lindsay Renwick, the mayor of Deniliquin, a country town in New South Wales, misses the constant whir(嗡嗡声)of the rice mill whose giant fans dried the rice. The Deniliquin mill, the largest rice mill in the Southern Hemisphere (南半球), once processed enough grain to meet the needs of 20 million people globally. But six years of drought have had a destructive effect, reducing Australia's rice crop by 98 percent and leading to the mothballing of the mill last December.

    Drought affects every agriculture industry based in Australia, not just rice – from sheep farming, the country's other backbone, to the cultivation of grapes for wine, the fastest-growing crop there, with that expansion often coming at the expense of rice. The drought's effect on rice has produced the greatest impact on the rest of the world, so far. It is one factor contributing to skyrocketing prices, and many scientists believe it is among the earliest signs that a warming planet is starting to affect food production.

    Researchers are looking for solutions to global rice shortages – for example, rice that blooms earlier in the day, when it is cooler, to fight against global warming. Rice plants that happen to bloom on hot days are less likely to produce grains of rice, a difficulty that is already starting to emerge in inland areas of China and other Asian countries as temperatures begin to climb. 'there will be problems very soon unless we have new varieties of rice in place,” said Reiner Wassmann, climate change director at the International Rice Research Institute (IRRI). The recent reports on climate change carried a warning that could make the news even worse: that existing models for the effects of climate change on agriculture did not yet include newer findings that global warming could reduce rainfall and make it more variable.

    Yet the effects of climate change are not uniformly bad for rice. Rising concentrations (浓度) of carbon dioxide, the main greenhouse gas, can actually help rice – although the effect reduces or disappears if the plants face unnecessary heat, inadequate water, severe pollution or other stresses. Still, the flexibility of farmers here has persuaded some climate experts that, particularly in developed countries, the effects of climate change may be relieved, if not completely avoided. “I'm not as negative as most people,” said Will Steffen, director of the Fenner School of Environment and Society at Australian National University. “Farmers are learning how to do things differently.”

    Meanwhile, changes like the use of water to grow wine grapes instead of rice carry their own costs, as the developing world is discovering. “Rice is an essential food,” said Graeme Haley, the general manager of the town of Deniliquin. “Wine is not.”

Phenomenon

Six years of drought reduced Australia's rice crop by 98%, leaving the rice mill____

____of drought and climate change

Every Australian agriculture industry is affected,____from sheep farming to the cultivation of grapes for wine.

The whole world is in____of rice.

Prices rise____ .

Temperatures begin to climb, causing____rice production.

____to global rice shortages

Seek a new variety of rice that blooms earlier when it is cooler as a____

Some good news

Unless faced with unnecessary heat, inadequate water or other stress, the main green house gas can actually do____to rice.

Farmers are flexible and they can do things____.