题干

表是某实验室指导老师上实验课时,记录整理的部分学生实验操作情况,请分析回答相关问题:

组别

材料

实验条件

观察内容

A

豆浆

0.1g/mL的NaOH溶液、0.01g/mL的CuSO4溶液等

液体的颜色变化

B

梨汁或苹果汁

0.1g/mL的NaOH溶液、0.05g/mL的CuSO4溶液等

液体的颜色变化

C

洋葱鳞叶表皮片

解离液、0.02g/mL的龙胆紫、显微镜等

有丝分裂的过程

D

紫色洋葱鳞片叶

0.5g/mL蔗糖液、显微镜、刀片、镊子等

液泡大小变化

E

菠菜叶

二氧化硅、碳酸钙、无水乙醇、层析液、定性滤纸、试管、玻璃漏斗、研钵等

叶绿体中色素的种类和颜色

(1)A组实验观察到的现象是液体发生了____ 

(2)B组实验注入试剂以后,对试管液体的处理方法与A组有何不同?____ 

(3)C组实验中,在显微镜下观察不到染色体,找不到有丝分裂的细胞,原因是____ ;如何修改实验____ 

(4)D组实验中,某同学发现洋葱鳞片叶细胞的紫色液泡很快缩小,但再用清水侵润该细胞后却不能复原,最可能的原因是____ 

(5)E组实验中碳酸钙的作用是____

上一题 下一题 0.0难度 选择题 更新时间:2017-06-05 02:03:32

答案(点此获取答案解析)

\u7d2b\u8272\u53cd\u5e94,A\u7ec4\u8bd5\u7ba1\u4e0d\u7528\u52a0\u70ed\uff08\u6216B\u7ec4\u8bd5\u7ba1\u9700\u8981\u6c34\u6d74\u52a0\u70ed\uff09,\u6d0b\u8471\u9cde\u53f6\u8868\u76ae\u7ec6\u80de\u4e0d\u8fdb\u884c\u6709\u4e1d\u5206\u88c2\uff0c\u4e0d\u51f

同类题2

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

    Trust has been considered as the basis of any relationship, including friendship. No relationship can last long with a lack of trust. Not many of your friends will have real faith in you as you would like to believe. ____ Sometimes, it takes years, even a complete lifetime, to trust someone. However, how do we know if our friends have faith in us?

    ____ With whom will you share things that you don't want everyone to know? It would be with a close friend, whom you trust as much as you trust yourself.

    Whom do you look up to for advice when you need it the most? It has to be either your parents or your friends. ________ This is a shining example of trust. You only seek advice from people you hold in high regard and find dependable. The friends who trust you will never forget to include you in the important decisions of their life.

    Arguments and heated discussions are a part of every relationship, and this is also true for friendship. ____ While some people find it difficult to forgive and forget, your friends will never have problems moving on. It is because they trust you and believe that you will never cause any pain to them on purpose.

    There are times in life when you find yourself a lonely soldier. ____ Your friends will never let you down and will strongly stand for you when you need encouragement. You can determine that they trust you and believe in your beliefs if they side with you when you need them the most.

A. People can be extraordinarily jealous sometimes.

B. You know they will never pass on a wrong suggestion.

C. In fact, winning trust is, by far, the most challenging aspect of relationships.

D. Two people can't have the same reactions to a situation and different opinions do exist.

E. No matter how close you are to your friends, you can't take that comfort level for granted.

F.If your friends share their secrets, there's a good possibility that they have much faith in you.

G. However, people fortunate to have been blessed with true friends are never alone in any battle.