Final answer:
The term used to represent the amount of oxygen in a given volume in a scuba diver’s tank is concentration, which specifically relates to the substance's presence in a mixture. The correct option is B.
Step-by-step explanation:
The term commonly used to represent the amount of oxygen in a given volume of a scuba diver’s tank is concentration. Concentration refers to the amount of a substance within a certain volume of solution or mixture.
While density represents the mass per unit volume, and pressure is the force exerted per unit area, concentration specifically deals with how much of a particular substance is present in a mixture. For gases, the concentration can also relate to the number of moles of gas present in a volume of space.
In the context of scuba diving, concentration is crucial as the diver must be provided with the right concentration of oxygen to the lungs, irrespective of the diving depth and the associated changes in pressure.