Answer the following question given this paragraph: 

Rainwater absorbs carbon dioxide (CO 2 ) as it falls. The CO 2 combines with water to form carbonic acid. The slightly acidic water is especially good at dissolving the rock limestone. Groundwater creates landforms by dissolving away rock.


Q: Rainwater absorbs carbon dioxide (co 2 ) as it falls. the co 2 combines with water to form what?

 Choices:

- carbon monoxide

- nitrate acid

- methane gas

- carbonic acid

A:
carbonic acid
