Question

When is it appropriate to use models?

Models should be used only when explaining submicroscopic matter.
Models should be used to complicate the phenomena so it is more realistic. Model should be used once they are completely accurate for all the scientific data. Models should be used when needed to explain or predict data being represented.

Answer 1

your answer should be the last one: models should be used when needed to explain or predict data being represented.

hope this helps :)