科学家做过如下的试验：
a.把不含生长素的两小块琼脂放在燕麦胚芽鞘下端（如图所示）
b.去胚芽鞘尖端，把含生长素的琼脂小块放在一段燕麦胚芽鞘形态学上端，把另两小块不含生长素的琼脂小块作为接受块放在下端
c.把一段燕麦胚芽鞘倒转过来，把形态学上端朝下，做与b同样的试验
三个试验都以单侧光照射。经过一段时间后，分析接受块①、②、③、④、⑤、⑥的成分变化，下列叙述正确的是                                        

如图中，曲线 X、Y、Z 分别表示食物中三类有机物在消化道中被消化的程度．其中能代表馒头消化程度的曲线是（　　）

增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：1）每处错误及其修改均仅限一词；2）只允许修改10处，多者（从第11处起）不计分。

    Last week, our teacher offered us an answer to a difficulty maths problem in class. Though an answer seemed a little strange, but nobody doubted it except me. Thinking that his answer might wrong, I carefully studied the problem and tried to work them out in a different way. Half an hour late, I managed to find the correct answer. When I show my answer to him, my teacher praised me of my independent thinking.

    From this experiences I have learnt that questioning can serve as a bridge that help us to find the truth.