In chemistry class, Mr  Zhang demonstrated two simultaneous teaching experiments: one is that O2 is produced slowly after KCIO3 heating; the other is that KCIO3 is heated and a small amount of MnO2 is quickly sprinkled into it, and a large amount of O2 is produced immediately
Teacher Zhang pointed out that MnO2 is the reason for the rapid production of O2
The higher the price of cosmetics of the same brand, the more popular it is. Thus it can be seen that consumers like cosmetics with high prices.