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
유행병학은 질병의 발생과 전파를 연구하는 학문입니다.yuhaengbyeonghak-eun jilbyeong-ui balseong-gwa jeonpareul yeonguhaneun hakmun-imnida.Epidemiology is the study of the occurrence and spread of diseases.