AlthoughtheCarbon14methodofdatingoldobjectsisnotfoolproof,itisthebestmethodavailableatpresent
A、whollyoperationalFormulatedin1823,theMonroeDoctrineassertedthattheAmericaswerenolongeropentoEuropeancolonization.
Communicationisoneofthemostimportantbondsthatholdculturalsystemstogether.
Alligatorsstillexistinsomeofthedank潮湿swampsandbayous小海湾ofAlabama'scoastalregions.
Someseaurchins海胆havevenomous(toxin)spines
Solidgeometryhasenabledastronomerstocalculatethepositionsoftheheavenlybodiesrelativetooneanother.