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
구이지학은 지구의 구조와 과정을 연구하는 학문입니다.guijihak-eun jigu-ui gujo-wa gwajeong-eul yeonguhaneun hakmun-imnida.Geology is the study of the Earth's structure and processes.