They can only expect to persuade others if they can argue convincingly and logically, rather than by sheer volume and insults. Remember too that disagreements should never be personal. Responsibility is crucial to a group's success. Each group as a whole has responsibility for achieving the final aims and objectives of the exercise or task. Each subgroup has responsibility for achieving their allocated role, and each individual has a responsibility to apply themselves as best they can to their particular part.
Individual responsibility extends further than that, however.
Within the project scenario, there will be plenty of scope to observe others work and see how their approaches to the problem differ from your own. Additionally, you will be able to observe their progress and work by looking at it on the web as time progresses. Criticism will be encouraged, and one of the things that you will learn during the course is how to criticise a piece of work. Criticism is the analysis of something that highlights the good and the bad in it. It should note the excellent ideas and innovations as well as pointing out the obvious and less obvious defects.