[名词解释] 海岸地貌

广州管圆线虫的中间宿主是 ["A．钉螺或拟钉螺","B．纹召螺和川卷螺","C．扁卷螺和豆螺","D．褐云玛瑙螺、福寿螺和蛞蝓","E．纹召螺和豆螺"] 蛔虫卵对外界环境抵抗力强的原因是 ["A．卵壳厚","B．具有蛋白质膜","C．具有受精膜","D．具有壳质层","E．具有蛔甙层"] 海岸带 机会性致病寄生虫是指 ["A．兼性寄生虫","B．专性寄生虫","C．偶然寄生虫","D．免疫功能正常时致病的寄生虫","E．免疫功能异常时致病的寄生虫"] 风成地貌 海岸地貌