把____个球,每____个装一盒,能装几盒?就是把____按照每____个为一份,分了____份.
算式:____÷____=____
A Spring Morning is my favorite poem its words are beautiful and I can feel the sense of spring in it.
如图所示,根据小磁针静止时的指向,标出磁体的N、S极和A点的磁场方向(用箭头表示).
如图中,A﹣E示意人体的不同结构层次,请据图分析回答下列问题
DNA分子复制的特点是( )