A.幼蟲(chóng)期行有性生殖,成蟲(chóng)期行無(wú)性生殖 B.成蟲(chóng)期行有性生殖,幼蟲(chóng)期行無(wú)性生殖 C.幼蟲(chóng).成蟲(chóng)均行有性生殖 D.幼蟲(chóng).成蟲(chóng)均行無(wú)性生殖
A.蟲(chóng)卵污染水源及水源中釘螺的存在 B.帶蟲(chóng)者和病人極多 C.有多種哺乳動(dòng)物作為保蟲(chóng)宿主 D.地方發(fā)生洪水或大暴雨
A.“+” B.“++” C.“+++” D.“++++”