Answer:
An increase in carbon dioxide in the atmosphere will MOST likely affect C: Cave formation rates .
Step-by-step explanation:
"Carbon-di-oxide" is an important gas which 'controls' the Earth's temperature. CO2 including methane are greenhouse gases which absorb a lot of energy and then re-emit it. Without these gases, earth would get frozen. But, if these gases are in excess, then temperature of earth would rise like that of Venus, up to 400 degree Celsius.
If CO2 increases, there will be an increase in cave formation activity. Rain water takes CO2 from the air and penetrates in the soil. This results in formation of "limestone" as 'carbonate' accumulates in the soil. This forms 'cave of limestone' with the help of 'groundwater' as limestone dissolves easily in water.