I could say off the top of my head that working in a group:
- Passes on skills to fellow team members
- Sharing ideas & thoughts on the experiment
- The experiment can be performed faster
if you need negatives you could say
- Some exclusion of team members may occur (i.e. Not sharing the experience and knowledge)
- Communications could become crossed causing errors or misunderstandings
- Some members may hinder the performance of the experiment
Hope this isn't too late to help