–Yes. She is an ________ girl from Shanghai.
A:eleven-years-old
B:twelve-year-old
C:eleven-year-old
D:twelve years old
能产生激素的细胞不一定能产生酶.
小明要用如图所示的实验器材探究电压一定时,电流热效应与电阻的关系,其中瓶内电阻丝的长度、粗细都相同.