—Why did you vote for Maggie?—Because she is very ________. She always shares things with others.
A:generous
B:active
C:practical
D:energetic
把蚕豆叶表皮浸泡在7%的尿素溶液中,开始时表皮细胞发生了质壁分离,然后自动复原,发生复原的原因是( )
①离体的植物器官、组织或细胞②根、芽③愈伤组织④脱分化
⑤再分化⑥植物体
下列各命题正确的是 : ( )