Gluclose for plants and humans

Which chemical equation is unbalanced? which chemical equation is unbalanced

The carbon cycle is best defined as a process in which a. carbon changes from inorganic forms to organic forms and back b. carbon is changed into other elements such as oxygen or nitrogen c. carbon is continually created from the sun’s energy by plants d. carbon is consumed and regenerated from other elements such as oxygen and nitrogen

How does the carbon cycle involve an exchange of carbon