Its renewed again and again by natural water cycle
This occurs when a molecule of adenosine diphosphate (ADP) uses the energy released during cellular respiration to bond with a thirdphosphate group, becoming amolecule of ATP. So the energy from cellular respiration is stored in the bond between the 2nd and 3rdphosphate group
Yes it is it usually
entirely
So you know that your measurements are exactly correct.
When you are constructing graph the independent variable always goes on the x-axis. Which is horizontally drawn.