Respuesta :
Sample answer for edge nuity: Testingg limestone with water provides a reference point, or control sample. It shows what happens if no chemical reaction and, therefore, no chemical weathering, takes place.
Answer:
Because the water acts as a base line or control test. Without this you could not 100% say that acidity has an effect on weathering, because there would be nothing to base your evidence to and compare it to non-acidic solutions.