[名词解释] 腐殖质

下列为良性溃疡的X线表现，错误的是 ["A．狭颈","B．项圈征","C．肩胛征","D．放射状黏膜纠集","E．溃疡口部黏膜线"] 专属吸附 下列有关溃疡型胃癌的X线征象，错误的是 ["A．放射状黏膜纠集，直抵龛影口部","B．不规则状黏膜纠集，杵状增粗","C．腔内龛影","D．指压迹","E．蠕动消失"] 天然水中的酸度 十二指肠溃疡好发于 ["A．球部","B．球后部","C．降部","D．水平部","E．升部"] 腐殖质