Which of the following is a limitation of temperature experiments on membrane permeability?

Ensuring equal lengths of time in water is crucial in temperature experiments on membrane permeability because variations in exposure time can directly affect the results. If samples are submerged in water for different durations, the amount of pigment released from the cell membranes may vary, leading to inconsistent data. This can obscure the relationship between temperature and membrane permeability.

In a controlled experiment, it's essential that all conditions remain constant except for the variable being tested—in this case, temperature. If the timing is not uniform, the experiment cannot accurately reflect how temperature impacts the permeability of the membranes, since the time factor significantly influences the extent of pigment leakage from the cells. Therefore, maintaining equal duration in water helps to ensure that any observed differences in pigment release are attributable solely to changes in temperature, making it a fundamental aspect of the experimental design.