when testing on the flies, how do you know that they are in a perfect, healthy condition, and the results arn’t due to

Question: when testing on the flies, how do you know that they are in a perfect, healthy condition, and the results arn't due to the state of the flie?

Asked by chloe to Mariam on 14 Jun 2010 in Categories: Your Research.
- Mariam Orme answered on 14 Jun 2010:
  
  That’s a very intelligent question Chloe.
  
  I keep all the flies in the same conditions – they all have the same food, they’re kept at the same temperature and so on – and these conditions are ideal for flies, so they should be happy and healthy. But sometimes they do get sick, and I can tell this if they’re not breeding properly, or if they get fungal infections (which is a bit gross!). So then I have to nurse them for a while until they’re healthy again.

Question: when testing on the flies, how do you know that they are in a perfect, healthy condition, and the results arn't due to the state of the flie?