This energy comes from the food we eat. Our bodies digest the food we eat by mixing it with fluids (acids and enzymes) in the stomach. When the stomach digests food, the carbohydrate (sugars and starches) in the food breaks down into another type of sugar, called glucose.
No, His data is not controlled. Being he let the younger siblings answer and they are not his classmates.
I'd say agriculture, though in more recent years you could argue for mining.
