A.螺螄的幼蟲(chóng) B.龍虱幼蟲(chóng) C.雙殼類蚌的幼蟲(chóng) D.蜻蜓幼蟲(chóng)
A.5ppm B.0.3ppm C.0.1ppm D.1ppm
A.個(gè)體大小 B.有無(wú)齒棘 C.胞核形狀 D.胞內(nèi)結(jié)構(gòu)