正确答案: C

孢粉素

题目：花粉粒外壁和内壁差别之一在于外壁含有( )。

解析：C

查看原题

举一反三的答案和解析：

[单选题]What does the word “this” underlined in the third paragraph refer to?

We will lose much more than we can gain．

[单选题]

surprise

[单选题]狗尾草的花序为穗状花序。( )

错误

[单选题]与乙国相比，甲国维持其在世界鲜切花市场竞争力的优势条件是

土地丰富，天然花卉品种较多

[单选题]It was a nice house, but _______ too small for a family of live.

rather

[单选题]31一Everybody is going to climb the mountain. Can I go too, mum?— Wait till you are old enough, dear．

I’m afraid not

[单选题]依次填入下面一段文字横线处的语句，衔接最恰当的一组是（3分）玉树藏族自治州___ ，______，_______，________，

④⑥⑤①③②

[单选题]

through