Answer:
1) ATP synthesis takes place in the mitochondria of eukaryotic cells.
(most ATP synthesis occurs there, but not 100%)
2) ATP is regenerated from ADP through the process of phosphorylation.
(phosphorylation means "to add a P")
3) Energy is stored in the covalent bonds between phosphates, with the greatest amount of energy in the bond between the second and third phosphate groups.
Step-by-step explanation: