Acidic water can react with limestone to break the rock down and form caves in the Earth's surface. This is an example of , which happens over time. A. physical weathering, quickly B. physical weathering, slowly C. chemical weathering, quickly D. chemical weathering, slowly

D. chemical weathering, slowly.

Explanation:took the test and got it right

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

: -)

the answer is:

carbon dioxide