Most universities possessing a school of Culinary Arts allow students to specialize in Pastry Arts which generally includes classes on chocolate. The alternative would be to enter an apprenticeship...
If you put it in the fridge melted chocolate will become hard again.
By machines. Watch Willy Wonka. That isn't real, but it gives you a clue!
it depends, if it starts in a winter season it will grow 5cm first year, but if sumer then about 8. Then about 10cm ever year after
That would be Dove chocolate.