Persuasion is used to help convince someone to do something or to agree with a different opinion. An example of this is when at work your employer wants to put a new rule into place, but most people don't like the idea of the rule, because they are thinking on a persona level only. So, you speak up and talk about all the possible benefits for everyone. And slowly people start agreeing to the idea of the rule because your small speech (persuasion) made sense.
You would need to introduce a list. For example you could have: My shopping list contains of; milk, bread, and yogurt. Another purpose is to separate clauses.
