某品牌饮用水标签标明了该水中钠、钾、钙等的含量,这里的钠、钾、钙等是指( )
A:原子
B:分子
C:元素
D:单质
— _______ is it from your home to your school, Anna?
— It's quite near, only five minutes' walk.
生物体能由小长大是通过( )