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
방실계의 전도는 심장의 기능에 매우 중요합니다.bangsilgyeui jeondoneun simjangui gungneun maeu jungyohamnida.Atrioventricular conduction is very important for the heart's function.