在维生素D的代谢中，有生物活性的物质是
A．维生素D2B．维生素D3C．7-脱氢胆固醇D．25-羟胆骨化醇E．1.25-二羟胆骨化醇
参考答案：E
Which of the following is the most widely accepted theory about the beginning of drama().
A.Drama came from seasonal changes.
B.Drama originated from ritual.
C.Drama evolved from stories.
D.Drama came from natural forces.
高血压的流行病学调查中，以下因素未确定与发病有关的是（）
A.体重
B.遗传
C.钠盐
D.精神应激
E.膳食中的脂肪
