What is a 'Non relevant sub topic'?
This sounds serious!!It can be.
You need to keep your sub topics relevant to the Main topic.
It can be about you but...
Example - One of your sub topics could be about Checking on my elderly neighbours.
BUT NOT..
Sub topic 1 - Save the Children (and other international charities)
Sub topic 2 - Why war is wrong
Sub topic 3 - Global famine
Note : the 3 topics above are not bad but you can easily get lost if you choose a BIG TOPIC.
Remember - You have 3 - 5 minutes presentation time