[{"hint": "Chemical energy in your body starts the chain.", "answer": "Chemical → kinetic (pedaling) → mechanical (wheels turning) → some thermal (friction/heat).", "question": "List three energy transformations that happen when you ride a bicycle."}, {"hint": "Think about the path electricity follows.", "answer": "Series has one path (if one component fails, all fail). Parallel has multiple paths (components work independently).", "question": "What is the difference between a series circuit and a parallel circuit?"}]