Final answer:
The term that most closely matches the definition given in the question, with an assumed correction from 'indirectly' to 'directly,' is Charles's law, which states that the volume of a gas is directly proportional to its absolute temperature when pressure is constant. The correct option is 2.
Step-by-step explanation:
The term that matches the definition of the volume of a gas varying indirectly with temperature, with pressure held constant, is Charles's law. Charles's law states that the volume of an ideal gas is directly proportional to its absolute temperature (in kelvins) when the pressure is held constant.
If the volume of a gas varies indirectly with temperature, that would imply an incorrect relationship since Charles's law specifies a direct variation between these two variables. None of the options precisely describes the situation where the gas volume varies indirectly with temperature while pressure is constant. Nevertheless, Charles's law is the closest to the definition provided if we consider a direct relationship instead of an indirect one. Hence, 2 is the correct option.