Why do we have different blood groups?

17 May 2010
Presented by Diana O'Carroll.

We discover some likely explanations for the different blood groups seen in humans. Is there any reason for having one blood type over another? Do other animals have them too? Plus, we ask: why do horses, donkeys and zebras all make different noises?

Add a comment

CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.