TheSalkvaccineisamajorfactorinthefighttoeradicatepolio.
A、completelydestroyBatsfly,ratherthanglide,andthusaretheonlymammalscapableoftrueflight.
DoubleEagleinthefirsttransatlanticballoon,wasgreetedbyavidcrowdsinFrance.
Thecontrolsofmostmodernairplanescanbeoperatedeithermanuallyorautomatically.
Someanimalspantandsweattospeedevaporationofbodymoistureandthuscoolthemselves.
Amythical(imaginary)creature,thedragonwasbelievedtohavelion'sclaws,scalyskin,andfierybreath.
