Hi Yes, all of that is good - Micro-organisms are the main thing that the speaker is going to talk about - It's a very general area of study - quite a broad one - I slightly prefer 'break', but either word is OK. It's a broad area of study, so we need to break it down into smaller subtopics I would definitely use a hyphen with micro-organisms Dave
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Rommel The main topic "microorganisms" is a broad one. You must divide / break it into subtopics.The main topic, "micro-organisms", is a broad one.