Xiao Chen's classmate Wei Zi.

1. The purpose is to compare the catalytic efficiency of potato and manganese dioxide. 2.a is large, because manganese dioxide needs to be heated to reach the active temperature. 3. Because catalase loses its activity at 0℃ due to low temperature, and this temperature difference has no obvious effect on manganese dioxide, B is much faster. 4. It is difficult to ensure the same amount of the two catalysts. It is impossible to know how many kinds of enzymes are in the potatoes used in the experiment.