Eyespots,themostrudimentaryeyes,arefoundinprotozoan原生动物flagellates鞭毛虫,flatworms扁形虫,andsegmentedworms片段蠕虫.
A、hostile-lookingDespitetheproliferationofotherfastermodesoftransportation,therailroadsremainthelargestcarriersofintercityfreightintheUnitedStates.
TheSalkvaccineisamajorfactorinthefighttoeradicatepolio.
Theflowerbudofawaterlily百合opensatsunsetsince.itsopeningistriggered(commence).bythedecreasedlight.
Someanimalspantandsweattospeedevaporationofbodymoistureandthuscoolthemselves.
Foodmustbemoistinordertohaveataste.
