Question: In 100 words or less explain exactly what the immune system does.

Mark Travis answered on 14 Jun 2010:

The immune system is made up of cells that recognise harmful pathogens that enter the body, getting rid of them quickly before they can cause us too much harm. The immune system is very clever in that it has ways of remembering pathogens, so if we are re-infected with the same thing we have a ‘memory’ to it and can get rid of it super quickly (which is the basis for us being vaccinated against certain things). The immune system also helps clean up any damage to tissues of body, and stops us getting infected if we cut ourselves.
(think that’s 99 words!)