Answer:
Hydrogen peroxide is toxic.
Explanation:
Hydrogen peroxide is a natural product of the reactions in the cell. However, it is toxic to cells and has to be broken down.
Catalase catalyses the breakdown of hydrogen peroxide into water and oxygen. It is found in all living cells and is very important to prevent the build up of hydrogen peroxide. If catalase didn't work quickly, hydrogen peroxide would accumulate in the cell and poison it, causing the cell to die.