Answer:
Around the world the most significant restriction on access to potable water is money. While access to raw water sources, clean or otherwise, is important, the purification process itself is expensive. Once water has been rendered potable, it is important that it be delivered without reintroducing contamination.
An example is the president vetoing a law that Congress passes. He can refuse to sign a bill.
A. the surface area of rocks decreases because of acid rain
I'm pretty sure its limestone, if not, then its sandstone
