Batsfly,ratherthanglide,andthusaretheonlymammalscapableoftrueflight.
A、straightEyespots,themostrudimentaryeyes,arefoundinprotozoan原生动物flagellates鞭毛虫,flatworms扁形虫,andsegmentedworms片段蠕虫.
Thewheelsofthefirstroadvehicleswerefashionedfromcrudestonedisks.
TheSalkvaccineisamajorfactorinthefighttoeradicatepolio.
Thefearofsmallpox,whichterrorizedtheeighteenthcentury,hasnoanalogy(likeness)today.
Someseaurchins海胆havevenomous(toxin)spines
