题干

在高等动物Z细胞的细胞周期中,各时期经历时间依次为G1期为8h、S期6h、G2期5h、M期1h.HU(羟基脲)是一种DNA合成抑制剂,对S期以外的细胞无影响,但可以阻止细胞进入S期而停留在G1/S交界(看作G1期细胞).科学家利用Z细胞和HU做了如下实验,每组设置多个重复样品.

①A组:培养液+Z细胞+HU(用生理盐水配置)

B组:培养液+Z细胞+生理盐水

②培养14h后,检测统计A、B两组各时期细胞数所占百分比(第一次检测).

③将A组中的HU全部洗脱,更换新鲜培养液培养10h,再向A组中加入HU.

④培养12h时间后,检测统计A、B两组各时期细胞数所占百分比(第二次检测).

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    I had the honor of being elected chief of my tribe(部落). With the title came great responsibility. It was my job to make peace with the Maori Tamaki tribe, whose village we visited. Their warriors leapt from a canoe and faced us down with fierce growls, bulging eyes and much swishing of sticks. They laid a palm frond on the ground and, as head honcho, I was compelled to accept this peace offering by picking it up, then touching noses with their chief. “Kia ora”, he said, welcoming us into the woodland home of his people.

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    Then they pulled our dinner of lamb, beef and vegetables out of the ground. It had been slow-cooked in the heat that simmers just below the surface in the geothermal(地热的) area of North Island, a Maori tradition known as a hangi that goes back an extremely long period of time.

    Obviously, this form of it is put on for tourists but it was hugely enjoyable. The journey back to the hotel was alone worth the effort, our hilarious Maori elder driver being deserving of his own television show. “The wheels on the bus go round and round,” he got us singing, while he circuited(绕……环行) a roundabout three times.

    A couple of days from the end of my trip, there was still something missing, a New Zealand icon I yearned to see to make my grand tour complete. Riding over a hill, there it was – Aotearoa. The Maori name for New Zealand translates as “Land of the long white cloud”. Can I say “Kia ora, Aotearoa?” You bet I can.