The plan________for a year,but no decision has________.
A:has been discussing;reached
B:is discussing;been reached
C:has been discussed;been reached
D:is being discussed;been reaching
正方形至少旋转____度能与自身重合.
下列属于无性生殖的是( )
①仙人球嫁接到仙人掌上
②鸡蛋孵化成小鸡
③草履虫通过分裂产生新个体
④大豆种子播种后长出大豆幼苗.