Final answer:
The method of mixing oxygen and fuel gas that uses higher pressure of oxygen employs an injector to properly mix the gases for combustion, which is reflected in various gas-based devices.
Step-by-step explanation:
When mixing oxygen and fuel gas, a method that incorporates higher pressure of oxygen uses a device known as an injector, which is part of the answer choice A) Injector. This method is utilized in various forms of gas-based equipment to ensure a proper mixture of gases for combustion. Examples of such devices include Bunsen burners, where air is entrained for combustion, or atomizers, which entrain liquid droplets into a stream of air. The process of entrainment often involves utilizing a high-speed fluid to create a region of lower pressure to successfully mix two substances. In more advanced technologies, like rockets or engines, the principles of mixing gaseous and liquid substances play critical roles in the combustion process needed for propulsion or power generation.