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
바다의 많은 생물들이 생물발광을 통해 빛을 발산합니다.bada-ui manheun saengmuldeuri saengmulbalgwang-eul tonghae bich-eul balsanhapnida.Many creatures in the ocean emit light through bioluminescence.