3D models are better than diagrams cause a diagram is flat, and its on a piece of paper, on the other hand 3D models have 3 Dimensions which show the model in a different view, they are also sometimes on paper but you have a better view if the model which helps you get more information of the diagram.
Hope I helped ya!! And plz put it under the right subject next time. This should go under Math.
A) To add medicines to foods that people eat