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
암석학은 암석의 구성과 성질을 연구하는 학문입니다.amseokhak-eun amseog-ui guseong-gwa seongjil-eul yeongu-haneun hakmun-imnida.Petrology is the study of the composition and properties of rocks.