题干

2007年11月下旬,美国和日本的两个研究小组几乎同时宣布成功将人体皮肤细胞改造成了几乎可以和胚胎干细胞相媲美的多功能干细胞﹣﹣“iPS细胞”,人类iPS细胞可以形成神经元等人体多种组织细胞.以下有关“iPS细胞”的说法中,正确的是(    )

A:“iPS细胞”分化为人体多种组织细胞的过程表现了细胞的全能性

B:“iPS细胞”有细胞周期,它分化形成的神经细胞没有细胞周期

C:“iPS细胞”既可分化形成神经元,也可用于制造心肌细胞,说明“iPS细胞”在分裂时很容易发生突变

D:“iPS细胞”只能分化成人体多种组织细胞是因为它不具有人体的完整基因组

上一题 下一题 0.0难度 选择题 更新时间:2019-11-11 06:28:13

答案(点此获取答案解析)

B

同类题2

完形填空

        It might have been a really bad stressful day, feeling trapped inside by the cold and snow which surrounded us.My husband got dressed and 1that he was going outside to build a giant snowman.

       At first he stood alone2massive amounts of snow.Soon after a neighbor joined in.Then we reluctantly put on our snow gear and3outside.It wasn't long4we were smiling and enjoying the 5of snow that Mother Nature had provided.Others came to our yard one by one to give a  6in the making of our giant snowman.

       In the end we all stood back and7at what we had created.He was eleven feet high, twenty­five feet around at the base and 8with many household items supplied by various9People drove by and smiled.Some even stopped just to enjoy his10

       With the passing of time, the spring made its 11back into our yard and the snowman changed form12In a final effort to save what we created for just a little bit 13somebody stopped by and changed the snowman's 14to look like a rabbit.As I prepared for the start of another week, I decided to 15my e­mail before going to bed.I found a (an) 16message that contained the subject line17the snowman.

       The e­mail said:your neighbor looks on in disbelief!Now you people are relishing(享受)the sounds and smells, along with18of spring.But I am sure people will never forget the 19energy displayed in Mr.Snowman.You and your family keep it up, as this is what the world needs now.More power to you and your loved ones, keep  20with the world around!

       Perhaps it was more than a snowman we built that day.The message seems clear.Our environments will turn out to be what we make of them.The possibilities are endless and the choice is ours.

Notes

①reluctantly adv.勉强地,不情愿地 ②disbelief n.不相信