题干

下图为将胡萝卜的离体组织在一定条件下培育形成试管苗的过程示意图。有关叙述正确的是(       )

A:利用此过程获得的试管苗可能为杂合子

B:①②过程中都会发生细胞的增殖和分化

C:多倍体植株的培育需经过如图所示过程

D:此过程依据的生物学原理是细胞膜具有流动性

上一题 下一题 0.0难度 选择题 更新时间:2015-01-12 05:54:31

答案(点此获取答案解析)

A

同类题1

阅读下列短文,从每题所给的四个选项(A、B、C和D)中,选出最佳选项。

     Joe is interested in getting exercise and competing (竞争) on a team. He reads about the events at the local pools and finds the perfect activity.

                                                                           Swimming Programs

     Summer Swim Team

     Join a Summer Swim Team and compete with other swimmers! The program is offered at eight different local pools for youths to 17 years old. The season runs June 21-August 21. Practices are daily (Monday through Friday) throughout the summer. Cost: $50.00.

Buckman

2-3 P.M.  

      Montavilla

8-9 A.M.

Creston

7-9 A.M.   

      Peninsula

4-7 P.M.

Dishman

8-9 A.M.

      Pier 

noon-1 P.M.

Grant

8-10 A.M.    

      Sellwood

7-9 A.M.

     Junior Swim Instructor (少年游泳教练)

     Two weeks, 20 hours of instruction, two hours per day for children 11-14 years old. Pre-training for youths interested in becoming swim instructors ($45 per child).

     Junior Lifeguard (救生员)

     Two weeks, 30 hours of instruction, three hours per day for children 11-14 years old. Pre-training in lifeguarding, and customer (消费者) service ($45 per child).

     Junior Swim Instructor & Junior Lifeguard Training Dates

June 28-July 9

August 9- August 20

June 12-July 23

August 23- September 3

June 26-August 6


     Special Offer

     Anyone who takes part in both junior swim instructor and junior lifeguard programs at the same time need only spend $75 instead of $90 for 50 hours of training.

     Register(注册) Online

     You can now register online! Visit our website at http://www.example.com. You can choose an area of town, a specific local center, a program, or search for classes which can meet the needs of students of different ages. Just visit our website, and you're on your way!

同类题5

阅读下列文章,完成下列小题。

苦瓜

肖复兴

       ①原来我家有个小院,院里可以种些花草和蔬菜。这些活儿,都是母亲特别喜欢做的。把那些花草蔬菜侍弄得姹紫嫣红,像是给自己的儿女收拾得眉清目秀、招人眼目,母亲的心里很舒坦。

       ②那时,母亲每年都特别喜欢种苦瓜。其实,这么说并不准确,是我特别喜欢苦瓜。刚开始,是我从别人家里要回苦瓜籽,给母亲种,并对她说:“这玩艺儿特别好玩,皮是绿的,里面的瓤和籽是红的!”我之所以喜欢苦瓜,最初的原因就是它里面的瓤和籽格外吸引我。苦瓜结在架上,母亲一直不摘,就让它们那么老着,一直挂到秋风起时。越老,它们里面的瓤和籽越红,红得像玛瑙、像热血、像燃烧了一天的落日。当我掰开苦瓜,兴奋地注视着这两片像船一样盛满了鲜红欲滴的瓤和籽瓜时,母亲总要眯缝起昏花的老眼看着,露出和我一样喜出望外的神情,仿佛那是她老人家的杰作,是她才能给予我的欧·亨利式的意外结尾,让我看到苦瓜最终这一落日般的血红和辉煌。

       ③以后,我发现苦瓜做菜其实很好吃。无论做汤,还是炒肉,都有一种清苦味。那苦味,格外别致,既不会传染上肉或别的菜,又有一种苦中蕴含的清香和苦味淡去的清新。

       ④像喜欢院里母亲种的苦瓜一样,我喜欢上了苦瓜这一道菜。每年夏天,母亲都会经常从小院里摘下沾着露水珠的鲜嫩的苦瓜,给我炒一盘苦瓜青椒肉丝。它成了我家夏日饭桌上一道经久不衰的家常菜。

       ⑤自从这之后,再见不到苦瓜瓤和籽鲜红欲滴的时候了,是因为再等不到那时候了。

       ⑥这样的菜,一直吃到我离开了小院,搬进了楼房。住进楼房,依然爱吃这样的菜,只是再吃不到母亲亲手种、亲手摘的苦瓜了,只能吃母亲亲手炒的苦瓜了。

       ⑦一直吃到母亲六年前去世。

       ⑧如今,依然爱吃这样的菜,只是母亲再也不能为我亲手到厨房去将青嫩的苦瓜切成丝,再掂起炒锅亲手将它炒熟,端上自家的餐桌了。

       ⑨因为常吃苦瓜,便常想起母亲。其实,母亲并不爱吃苦瓜。除了头几次,在我一再的怂恿下,勉强动了几筷子,皱起眉头,便不再问津。母亲实在忍受不了那股子异样的苦味。她说过,苦瓜还是留着看红瓤红籽好。可是,她依然每年夏天当苦瓜爬满架时,为我清炒一盘我特别喜欢吃的苦瓜肉丝。

       ⑩最近,看了一则介绍苦瓜的短文,上面有这样一段文字:“苦瓜味苦,但它从不把苦味传给其他食物。用苦瓜炒肉、焖肉、炖肉,其肉丝毫不沾苦味,故而人们美其名曰‘君子菜’。”不知怎么搞的,看完这段话,让我想起母亲。