Final answer:
Charles's Law establishes the direct relationship between the temperature (independent variable) and volume (dependent variable) of a gas at constant pressure. The answer to the question is b) Temperature; Volume, emphasizing the direct proportionality between these two properties when pressure is maintained.
Step-by-step explanation:
For Experiment I, which relates to Charles's Law: The independent variable is temperature and the dependent variable is volume. This means the correct answer is b) Temperature; Volume. Charles's Law states that the volume of a given mass of gas varies directly with the absolute temperature of the gas when pressure is kept constant. The relationship is described as a direct proportionality, where the volume of a gas increases with an increase in temperature (measured on the Kelvin scale) when pressure is constant.
According to Charles's Law, when conducting an experiment under conditions of constant pressure, if you alter the temperature of the gas, the volume will respond accordingly. Hence, the temperature is the variable that you control (independent) and the volume is the variable that changes as a result (dependent).