The Native American interpreter Sacajawea was a valuable member of the Lewis and dark expedition in 1805.
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Eyespots,themostrudimentaryeyes,arefoundinprotozoan原生动物flagellates鞭毛虫,flatworms扁形虫,andsegmentedworms片段蠕虫.
TheSalkvaccineisamajorfactorinthefighttoeradicatepolio.
ThefirstimportantexpositionintheUnitedStateswasheldinPhiladelphiain1876.
Despitetheproliferationofotherfastermodesoftransportation,therailroadsremainthelargestcarriersofintercityfreightintheUnitedStates.
Batsfly,ratherthanglide,andthusaretheonlymammalscapableoftrueflight.