Which two factors are critical to the existence of the carbon dioxide (CO2) cycle on Earth?
A. life and atmospheric oxygen
B. life and active volcanism
C. plate tectonics and liquid water oceans
D. active volcanism and active tectonics
Answer:C
Which two factors are critical to the existence of the carbon dioxide (CO2) cycle on Earth?
A. life and atmospheric oxygen B. life and active volcanism C. plate tectonics and liquid water oceans D. active volcanism and active tectonics