题干

在离体的植物器官、组织或细胞形成愈伤组织的过程中,下列哪些条件是必需的 
①无菌空气        ②充足的光照         ③适宜的温度  
④适宜的养料和激素      ⑤消毒灭菌     ⑥适宜的水分  

A:①③④⑤⑥

B:②③④⑤⑥

C:①②③④⑤⑥④

D:③④⑤⑥

上一题 下一题 0.0难度 选择题 更新时间:2019-06-15 07:48:16

答案(点此获取答案解析)

A

同类题4

Dear Disney,
   Last weekend, the four members of my family spent an enjoyable holiday at the Magic Kingdom - Disneyland. And one event made our visit seem truly magical. We got to the front of the line at Space Mountain, only to find out that our little daughter Gloria couldn't take her ice-cream on the ride. We were so excited that we all forgot ice-cream was not allowed on the ride.

   Gloria broke into tears and we all had no idea what to do. Then Murphy, one of the staff(员工) members, came over. She bent down and told Gloria that she would hold the ice-cream for her and give it to her when she finished the ride. Gloria said, "Promise?" Then she gave Murphy her ice-cream, and she completely enjoyed the ride.
   Sure enough, as we walked out the exit, there was Gloria's new friend with "her" ice-cream. Now you and I both know what happened, because we know that an ice-cream won't last twenty minutes on a summer afternoon in Florida. Murphy knew' what time we would get off the ride; she went to the nearest shop and bought a brand-new ice-cream thirty seconds before we walked out the exit. Gloria said, "Thank you," but I'm sure she thought it was the same ice-cream.
   We know that someone tried hard to make our visit special. Thanks so much for going above and beyond!                                                                                                                                                                                                 Your fan,                                                                                                                          Carmen Rivera