题干

紫色水萝卜块根细胞的液泡中含有呈紫红色的花青素,将块根切成小块放入清水中,水的颜色无明显变化.若进行加热,随着水温的增高,水的颜色逐渐变红,其原因是(    )

A:细胞壁在加热的过程中受到破坏

B:水温增高,花青素的溶解度加大

C:加热使膜失去了选择透性

D:加热使细胞壁失去了选择透性

上一题 下一题 0.0难度 选择题 更新时间:2018-02-02 03:30:26

答案(点此获取答案解析)

C

同类题4

书面表达

假如你是某英语杂志社编辑王林,根据下面中学生小明的来信,给他写一封回信,解答他的困惑。

要求:1. 观点鲜明,结构合理,内容连贯;

2. 词数80左右,信的开头和落款已给出,不计入总词数。

Dear editor,

   Nowadays, many junior high school students are completely getting relaxed from busy study after graduation,  so what they would like to do most is to throw books away, hang out with friends at daytime and stay up late at night playing computer games or watching TV. What's your opinion about this? I'm looking forward to your reply.

                                                                                                                                                                                                      Yours sincerely

         Xiaoming

Dear Xiaoming,

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Yours,

Wang Lin