Why do group discussion participants need to gather facts? to support their opinions to show they can do research to prove they have opinions to manage the discussion’s flow? !

The correct answer would be "To support their opinions".

In any kind of group discussion there will most likely be a variety of opinions. The flow will be dictated by the ability of each participant in expressing serious interpretations in a respectful manner. The role of fact presentation or data gathering isn't to prove that you can do research but to make your point stronger with empirical facts, statistics or studies that bring an element of objectivity.

Hope this helps!

A. Support their opinions.

well to answer ur question to be completly honest

taking a bath requires the most water out of the given options because it takes a significant amount of water in order to fill a bathtub.