Water mixing with carbon dioxide from the air and changing the properties of limestone is an example of

i think the answer is c, rivers.

explanation:

sometimes, borders fall along natural boundaries like rivers or mountain ranges. for example, the boundary between france and spain follows the crest of the pyrenees mountains. for part of its length, the boundary between the united states and mexico follows a river called the rio grande. the borders of four countries divide africa’s lake chad: niger, chad, cameroon, and nigeria.

unbeknownst to the slave-ship captains, the daily dancing and exercise regime and vernacular dance are also derived from america's african-based slave legacy. both are african-american cuisines from the slavery era.

explanation: