I need help with physioex version 8.0 exercise 8

Activity 1, right?

Tubes 2, 6, and 7 showed the effect of pH on amylase activity. The results of this experiment
indicate that the activity maximum of amylase is at pH 7.0, whereas pH 2.0 and pH 9.0 demonstrated very little activity. In this experiment, pH 7.0 showed the highest level of amylase activity. Tube 3 showed that amylase did not contain maltose contamination. Tubes 3, 4, and 5 showed that water had no starch or maltose contamination. Tube 3 directly showed that water did not have maltose or starch contamination. Tube 4 was a starch control (with the same water) that showed no maltose, and tube 5 was a maltose control (also with water) that showed no starch. If control tubes 3, 4, or 5 were not done, then what is perceived as digestion might really be starch or maltose contamination. Saliva would not be active in the stomach because the stomach pH is too low. Boiling inactivates, or denatures, enzymes.