John wants to test how temperature affects the mass of sugar that can be dissolved in water. Which of the following factors must be the same between the control group and the experimental group?

In John's experiment, factors that must remain the same between the control group and the experimental group include the volume of water used, the type and amount of sugar, and the duration of stirring or mixing. These constants ensure that any observed changes in the mass of sugar dissolved are solely due to variations in temperature. Additionally, the starting temperature of the water before heating or cooling should also be controlled.