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
하천학은 강과 하천의 생태계를 연구하는 학문입니다.Hacheonhak-eun gang-gwa hacheon-ui saengtaegye-reul yeongu-haneun hakmun-imnida.Fluviology is the study of the ecosystems of rivers and streams.