This figure is a graph. The y-axis is labeled "reaction rate," while the x-axis is labeled "PH." The x-axis ranges from 0 to 14. The plot line is U-shaped, beginning approximately three quarters of the way up the y-axis and gradually dipping down to its low point at a PH of 6. The plot line then gradually rises again to its highest point at a PH of 12. It then dips back down to about three quarters of the way up the y-axis at a PH of 14. Image Courtesy of 3DScience. com The graph above shows the progress of an enzyme-catalyzed chemical reaction. Based on the graph, this enzyme is minimally active between pH 5-7 works optimally between pH 5-7 is minimally between pH 0-3 works optimally between pH 0-3