纸条上四种色素的排列顺序正确的是（）①叶绿素a②叶绿素b③胡萝卜素④叶黄素
A.①②③④
B.③④①②
C.②①③④
D.④③①②
参考答案：B
原发性痛风最主要的发病机制为
A．磷酸核糖焦磷酸合成酶活性增强B．次黄嘌呤-鸟嘌呤磷酸核糖转移酶缺乏C．胰岛素抵抗D．尿酸排泄减少E．尿酸生成增多
Since it was so difficult for American Indians to negotiate a peace treaty or declare war in their native language, they used a universal understood form of sign language.
