In this chemistry challenge, learners identify which plants have the enzyme "catalase" that breaks hydrogen peroxide into water and oxygen. Multiple fruits and vegetables, both raw and cooked (a few seconds in boiling water, or 30 seconds in the microwave) should be available for testing. Preparation time can be shortened by using a food processor. Background information is provided about enzymes (proteins that act as catalysts), and the specific enzyme catalase, which catalyzes hydrogen peroxide. Since heating destroys enzymes, cooked fruits and vegetables have no catalytic activity.