单位面积上苗床所铺设的电热线功率为(),总功率为()与()的乘积。
参考答案:功率密度;功率密度;苗床面积
It was for this reason _____ her uncle moved out of New York and settled down in a small village. [ ]
A. which
B. why
C. that
D. how
()在原生动物细胞中不可能被发现。
A、线粒体
B、高尔基体
C、溶酶体
D、细胞壁