在平面直角坐标系中,O为原点,点A(4,0),点B(0,3),把△ABO绕点B逆时针旋转,得△A′BO′,点A、O旋转后的对应点为A′、O′,记旋转角为ɑ.
⑴New Year____ A. in January or February
⑵Chinese New Year____ B. on the third Sunday in June
⑶Mother's day____ C. on 1st January
⑷Father's day____ D. on the second Sunday in May
⑸Children's day____ E. on 1st June
(1)从细胞元素构成的角度,请简要概括生物与无机自然界的统一性和差异性____
(2)线粒体和叶绿体各存在于什么细胞中?请各用一句话概述____,中心体存在于什么细胞中?____有没有一种细胞同时含有上述三种细胞器?____
(3)请简述主动运输的意义____
(4)斐林试剂与双缩脲试剂都由NaOH和CuSO4组成,简述两者存在哪几个方面的不同? ____ ____