Final answer:
The activity that involves the heat from fuel gas combustion in the presence of oxygen is cooking on a gas stove. Combustion is an exothermic reaction releasing heat, necessary for activities like cooking.
Step-by-step explanation:
The activity that depends on the heat produced by the combustion of a fuel gas in the presence of oxygen is cooking on a gas stove. When cooking on a gas stove, the fuel typically used is natural gas, which consists mainly of methane, and burns in the presence of oxygen to produce heat. This heat is what allows us to cook food. In contrast, charging a smartphone relies on electrical energy, riding a bicycle depends on mechanical energy, and watering plants does not involve the combustion of fuel.
Combustion reactions are exothermic reactions because they release energy in the form of light and heat, and they require oxygen as a reactant. The combustion of hydrogen gas, for example, produces water vapor as it reacts with oxygen. This principle is applied in technologies like fuel-cell vehicles (FCV), which use hydrogen to generate electricity through a chemical reaction with oxygen, offering a potentially more efficient and environmentally friendly transportation option compared to conventional vehicles with internal combustion engines.