Forseveralbillionyearsafterthe“BigBang”,theearthwassti...
2019-03-13
問題詳情: Forseveralbillionyearsafterthe“BigBang”,theearthwasstilljustacloudofdust.Whatitwasto______(36)wasuncertainuntilbetween4.5and3.8billionyearsagowhenthedustsettledintoasolidglobe.Theearthbeca...