How is the balance of Oxygen and Carbon dioxide in maintained in nature​

What was one of the difficulties adams faced as president? a. european countries were trying to move back in on u.s. lands b. possible war with england; fighting between political parties c. problems with spain; trade disputes with russia d. census issues; problems with selecting a new capital

What is the tallest mountain range in south america? a guiana highlands b the patagonia mountians c the andes mountians d brazilian mountains

Who coined the phrase “go west and grow with the country”?