The following leaf disk experiment performed:
Twenty 5 mm diameter disks were ‘punched’ out of spinach leaves and placed into a plastic syringe. A small volume of 0.2% sodium bicarbonate solution was drawn into the syringe, and a vacuum was created to saturate the leaf’s air spaces with the solution. After all of the disks had sunk in the syringe, they were transferred into a clear plastic cup filled with bicarbonate solution. They were then placed under a light source, and a timer was started.
At the end of each minute, the number of floating disks were recorded.
Which of the following would be a valid question that can be asked about this experimental protocol?