How the sex chromosomes decide sex in humans, and how X-linked and Y-linked traits such as colour blindness and haemophilia are inherited.
Deshapriya Senevirathne. B.Sc. (Hons) Biology Special, University of Peradeniya — graduated with a class pass. All the content and lessons in A/L Biology on Paadama are reviewed by Deshapriya Senevirathne, and the lessons are taught by him.