据有关资料介绍，儿童缺钙会得佝偻病，成年人缺钙会得软骨病，血液中也有少量钙，它对皮肤伤口血液的凝固起着重要作用；人体缺碘会引起甲状腺肿大。这里的“钙”、“碘”是指（）_刷题宝

题干

据有关资料介绍，儿童缺钙会得佝偻病，成年人缺钙会得软骨病，血液中也有少量钙，它对皮肤伤口血液的凝固起着重要作用；人体缺碘会引起甲状腺肿大。这里的“钙”、“碘”是指（）

A：单质

B：元素

C：原子

D：分子

上一题下一题 0.0难度选择题更新时间:2017-06-13 12:30:17

答案(点此获取答案解析）

B

同类题1

There was an ____(尴尬地) long silence..

同类题2

My cousin is ____(heavy) than my brother.

同类题3

在水平方向上做简谐运动的质点,其振动图像如图所示。假设向右的方向为正方向,则物体的位移向左且速度向右的时间段是(　　)

同类题4

根据对话内容和汉语提示，用适当的表达完成对话。

A: Where is Jim? He isn't at school today.

B: I ____ (认为他不能) come to school today.

A: Why not?

B: He has to ____ (呆在家) and look after his mother.

A: ____ (怎么了) with his mother?

B: She ____ (得了重感冒) yesterday.

A: I'm sorry to hear that. Did she ____ (看医生)?

B: Yes. The doctor said she had to lie down and rest ____ (几天).

A: I hope she ____ (快点儿好起来). Then are you free after school?

B: Yes. Why?

A: Let's go to see him and take the homework to him.

B: That's a good idea.

同类题5

长方体的顶点数、棱数、面数分别是（）

小学学科试题库

初中学科试题库

高中学科试题库