(10分)(1)C:注射EPO试剂,正常氧环境饲养(1分)②实验开始时和实验中每隔一段时间,分别用EPO含量测定仪测定每只小鼠血液中的EPO浓度,用血细胞计数板在显微镜下计数红细胞数量,并记录。(1分)(2)(3分)红细胞B组数目组A组时间低氧和EPO刺激对红细胞生成情况的影响曲线图说明:图名、图注、坐标系各0.5分,三条曲线各0.5分。曲线A保持稳定,并且最低曲线B比C较迟稳定平衡,但两学科网曲线的高低关系不作要求(3)(5分,每空1分)①左上→右上→右下→左下②受体造血干细胞③红细胞含量增加,血液含氧量增加,EPO合成和分泌量减少负反馈

第二节(满分25分)The nert morming, Devin went straight to the music room. "I am not the best singer and I have to."Devin hesitatedOne possible versionwith his eyes fixed on the floor. Ms. Poltis smiled warmly, "I choose you because you work hard, like the person in the song.So don't be nervous! " Devin raised his head and looked at her, tears welling up in his eyes. It was at that moment that Devinmade his final decision. Later that day, Devin went to his coach and teammates. Unexpectedly, they welcomed him andOn Thursday evening, Devin felt a little nervous to see so many people in the concert halL. Devin took a deep breath andpromised that they would spare no effort to win the title.stepped onto the stage, The bright light coming on, Devin calmed down and sang with confidence. Devin handled the soloperfectly. Hardly had he finished the last word of the song when a wave of applause erupted from the audience. Devin smiled atMs. Poltis and felt proud of the choice he had made. No matter how hard the struggle, you have to make a decision and neverlet yourself down.

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