Can the changes observed in the circuit boa d during the etching process serve as evidence that the starting and final substances change?

A. Yes, because the circuit board becomes thinner and more delicate
B. Yes, because the circuit board becomes harder and more rigid
C. No, because the circuit board does not change during the etching process
D. No, because the circuit board becomes softer and more flexible

A. Yes, because the circuit board becomes thinner and more delicate

The changes observed in the circuit board during the etching process, such as becoming thinner and more delicate, serve as evidence that the starting and final substances have changed.