Q: Answer the following question given this paragraph: An example of a physical model is a drawing of the layers of Earth ( Figure below ). A drawing helps us to understand the structure of the planet. Yet there are many differences between a drawing and the real thing. The size of a model is much smaller, for example. A drawing also doesn't give good idea of how substances move. Arrows showing the direction the material moves can help. A physical model is very useful but it can't explain the real Earth perfectly. Q: What was diorite commonly used for in ancient civilizations? A:

OPT:
a). school.
b). currency.
c). medicine.
d). art.
A:
d).