I will use the best possible way to make the person understand that specific category of biology, I personally create power point for the people that don't understand that category of biology, but to create this power point I will need to request the person to tell me about what he/she don't understand about biology, I will personally research about that specific category of biology that he/she don't understand, I will make the PowerPoint as simple as possible so when I am explaining him/her they will understand that category of biology.