A:区域Ⅰ的细胞经历伸长生长即可形成区域Ⅲ的细胞
B:区域Ⅰ的细胞能合成生长素,促进区域Ⅱ细胞的伸长生长
C:区域Ⅲ的细胞大部分处于分裂间期
D:若外界溶液浓度较低,区域Ⅰ的细胞主要通过渗透作用吸水
已知a+b=2,a﹣b=3,则a2﹣b2=____ .
“竹外桃花三两枝,春江水暖鸭先知.”这句诗描述的是哪一种非生物因素影响了鸭的生活( )
下列自然资源中,属于非可再生资源的是( )
根据短文,选择正确答案。
Some cats are black. Some cats are white. Some cats are black and white. But no cats are green. I have a mother cat. She has three sons and two daughters. The mother cat loves her sons and daughters and they love their mother very much. And she looks after them.
假期去郊外游玩时,经常会看到远处有许多小鸟停在电线上.对于小鸟栖息在高压线上而不会触电,以下解释中合理的是( )