You are giving your hypothesis.
You would still have 651 g of a certain compound but in different products, so the splitting of water via electrolysis you still have 2 Hydrogen and 1 Oxygen.
A food web demonstrates which organisms transfer energy to other organisms. It helps maintain the ecosystem because if one life form went extinct, it could destroy the whole web.
Generally someone 120 pounds would use a 12 pound ball
2) ADP is similar to rechargeable batteries because it can be continuously combined with inorganic phosphate to produce ATP which is hydrolysed in any energy requiring process back to ADP which can be recombined with inorganic phosphate to reproduce ATP.
3)ATP is manufactured in the mitochondria.
4) Not sure what a macromolecule is. (I did the old GCSE.)
5) From the electron transport chain when electrons gradually lose energy (from photo-excitation) as they are passed from one electron carrier to another.
