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
화석산호는 고대 해양 생물의 중요한 증거입니다.hwasuksanho-neun gode haeyang saengmul-ui jungyohan jeunggeoimnida.Fossil coral is an important evidence of ancient marine life.