可刺激肥大细胞脱颗粒释放生物活性介质的补体成分是（）
A.C1q
B.C3b
C.C5a
D.C4b
E.C2a
参考答案：C
解析：C3a、C4a、C5a作为配体与肥大细胞、嗜碱性粒细胞、中性粒细胞、单核巨噬细胞和内皮细胞表面相应受体结合，激发细胞脱颗粒，释放组胺之类的血管活性介质，从而增加血管通透性并刺激内脏平滑肌收缩，称过敏毒素。C5a还是一种趋化因子。
根据对话内容，从方框中的六个选项中选出五个合适的句子补全对话。 Linda: Hello, 76_____________ . Peter: I’m reading a book about the people’s lives in the future. Linda: Oh, it’s interesting. What will the people’s lives be in the future? 77________ Peter: Yes, I think so, but I hope not. Linda:78________ Peter: Because there won’t be enough food, fuel and room for too many people on the earth! Linda: That’s true. 79_______ Peter: It’s too hard. But maybe people will have on space stations (空间站) on the moon and grow vegetables (种植蔬菜)there. Linda: 80______. By the way, do you think everyone will speak the same language in the future? Peter: I hope so. Then people in different countries will understand each other better.
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