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
물고기의 삭개는 수조의 수위를 조절하는 데 도움을 줍니다.mulgogiui sakkyeun sujo-ui suwido jeojulhaneun de doumeul jumida.The operculum of the fish helps regulate the water level in the tank.