题干

最近,广州中山医院的科技人员进行了一项新的研究:他们将一只老鼠的肝脏切除,并在肝脏部位移植上老鼠的胚胎干细胞。这些干细胞在药物的诱导下,最后又长出了新的肝脏。这个从胚胎干细胞变为新肝脏的过程,相当于细胞的(   )

A:分裂、生长

B:生长、分化

C:分裂、分化

D:分裂、生长和分化

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答案(点此获取答案解析)

D

同类题5

阅读下列短文,从每小题所给的A、B、C、D四个选项中选出一个最佳选项。

    Answers to life can be found in everyday events. Watching nature, watching people and watching animals communicate with each other provide some of the simplest ways to life's biggest problems.

    This became clearer to me yesterday. It caused me to ask myself, “How do I respond (反应) to the storms in life?”

    People usually run when it starts to rain. I love to walk in it, stand on my front door and feel it. I grew up doing it and have never really felt the fear many people do.

    The animal world senses changes in the weather far earlier than humans. My dog, Ricky, begins to shake long before the storm is close enough to be noticed. I was about to feed my three dogs yesterday and as usual, I let them out in the yard first. They didn't move when thunder came across the skies. So I placed their food in their bowls and called Ricky into the kitchen.

    Ricky was just standing there in place next to his bowl. The thunder became louder, which forced him to stop eating his meal. Then I watched Phil. He made his way across the kitchen floor and stood over Ricky's bowl. He ate all the remaining food. Generally, if Ricky was standing there, he wouldn't dare (敢) come close. But today, he took advantage (优势) of the storm and got what he wanted. His hope for the prize outweighed (胜过) his fear of the storm.

    That's when it hit me. As men, we face all kinds of storms. They come in unannounced. Sometimes we stay in a corner or under the blankets, hoping it will all pass. However, if you dare put your head out, you'll discover there're people doing what they must to get what they must have out of life. Isn't it time you decided to take advantage of the storm?