Hello guys, Welcome to Africa's Largest Video Search Engine, and you are watching Active & Passive immunity | Human health & diseases | Subject | Khan Academy. and this video is uploaded by Khan Academy India - English at 2021-12-09T04:56:45-08:00. We are just promoting this video only for entertainment and educational purpose only. I hop you like our Video Search Engine. [2EKIqr4T8Ng]