Problem 1: Which direction did the yellow oxygen molecules move: into or out of the cell? Does this indicate the molecules are moving from a low to high concentration or a high to low concentration?
Problem 2: When you start moving your body, the oxygen inside your muscle cells is consumed and oxygen levels drop. What did you notice about how long it took to reach equilibrium (yellow bars about equal) in the second run versus the first? Why do you think this happened?