Which statement about the carbon cycle is most true? A. Energy is destroyed when organic matter decays.
B. The total mass of carbon on Earth is always increasing.
C. Carbon is lost from the cycle when it enters the atmosphere.
D. Carbon changes form, but the total amount on Earth remains the same

i think the answer is a, hope this is right, that would be my best guess.

  distance on the y-axis and time on the x-axis.

explanation:

the instantaneous velocity = change in position/time taken

the slope of the graph should give instantaneous velocity.

  slope of a graph = change in value of y -axis / change in values of x -axis

  comparing both the equations

    change in value of y -axis = change in position

  change in values of x -axis = time taken

so position values should be on the y axis and time values should be on the x axis.

distance on the y-axis and time on the x-axis.