Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
오르도비스기는 고생대의 두 번째 지질 시대입니다.oreudobiseugi-neun go saengdae-ui du beonjjae jiljil sidae-imnida.The Ordovician is the second geological period of the Paleozoic era.