Define the three primary energy systems?What is the purpose of each?

The Three Primary Energy Systems

1. Define the three primary energy systems?
2. What is the purpose of each?
3. Where do they take place?
4. What processes &/or cycles is aerobic metabolism composed of?
5. How do they (processes, reactions, cycles, etc) work?
6. How much ATP is produced aerobically from each process/cycle/substrate?
7. Explain how energy systems impacts exercise and athletics?