题干

干细胞是一种尚未充分分化的未成熟的细胞,它具有再生各种细胞、器官的潜能,医学家们正尝试利用干细胞治疗一些顽疾,用骨髓移植法治疗白血病便是成功的例证。下列说法中不正确的是(   )

C:用骨髓移植法治疗白血病的优点之一是不发生排斥(异)反应

A:利用干细胞治疗某些顽疾,是因为干细胞具有再生各种组织、器官的潜能

B:骨髓分为红骨髓和黄骨髓,其中,只有红骨髓具有造血功能

D:异体骨髓移植成功后,康复者的血型有可能发生改变

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答案(点此获取答案解析)

C

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阅读理解

    Captain(船长)Nemo invited me and my friends to go hunting with him in the forests of Crespo Island. I asked him why he was so interested in Crespo Island. “I thought you preferred the sea to being on land.”

    “I do,” replied the captain. “But these forests are under the sea.”

After going through a door, we were about ten meters under the water. The light from the sun reached us. Everything looked very colourful. We were going deeper and deeper. At 100 meters deep, we could see quite well, and Captain Nemo stopped and pointed to some dark shapes. This was the forest. The “trees” in the forest were giant seaweed, and all their “branches” were vertical(垂直的).We could not stop looking at them. Fish swam around the branches like birds in a forest.

    Suddenly, I saw a large sea spider about a meter tall. It was going to attack me. Captain Nemo's man killed it with his gun, but it reminded me that the sea could be as dangerous as it was beautiful. When we reached 150 meters, it was dark. The sun's light could not reach this depth(深度). We turned our lights. We could see about 20 meters around us. Finally, we found Crespo Island—where a steep rock wall rose in front of us.

    We could go no further, so we walked back toward the Nautilus. Suddenly, Captain Nemo stopped and shot an animal with his gun, it was a beautiful and rare sea otter. At last, we could see the Nautilus. Several large sharks swam over us. Luckily they didn't see us. We re-entered the Nautilus safely. I was tired but amazed by what I had seen.