The overall order of a reaction is directly
related to the reaction mechanism of the reaction. The reaction mechanism is
defined by the reaction rate equation. In this case, we are given by the
equation, Rate=k. The order of this reaction is zero since the rate is
not dependent on the concentration of reactants or products.
Because it is balanced with protons and electrons
Not exactly chemistry but ok.
Phó is one of the famous dish in Vietnamese Culture
Hence, the answer is Vietnamese Cuisine