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
산호초는 바다 생태계에서 중요한 역할을 합니다.sanhoccho-neun bada saengtaegyeeseo jungyohan yeoghal-eul hamnida.Coral reefs play an important role in the marine ecosystem.