Final answer:
The delta G for burning sugar in a furnace is exergonic, while the delta G for breaking down sugar in the human body is endergonic.
Step-by-step explanation:
In a furnace, the combustion of sugar is a rapid chemical reaction that combines molecules of oxygen with molecules of fuel, converting the energy stored in the fuel to heat. This reaction is exergonic, meaning it releases energy. On the other hand, in the human body, sugar is broken down through the process of cellular respiration, which is a slower and more controlled process. This reaction also involves combining oxygen with sugar molecules, but the energy released is used by cells to perform work, making it endergonic.