Answer:
a. add a little distilled water to see which layer the water adds to
Step-by-step explanation:
The problem tells us to keep in mind two major aspects of the test: It has to be simple, as well as non-destructive:
- Adding distilled water can be made in under a minute, without requiring specialized laboratory equipment, unlike IR.
- It is also non-destructive, because the contents on either layer won't change due to the added distilled water.