Question

compare the planet sizes from your lab to the planetary distances you just saw in the graph. why is it so difficult to show both on the same model?

Explanation:

The sizes of planets vary greatly and the distances between planets are extremely large. The scale differences are so significant that representing both accurately on the same model is difficult. A model that shows planet sizes in - proportion would make the distances between them too large to fit, and a model that shows distances accurately would make the planet sizes appear minuscule.

Answer:

The vast differences in scale between planet sizes and planetary distances make it difficult to show both on the same model.