question: What are catalysts in living things called?
distractor3: carbohydrates
distractor1: proteins
distractor2: carbohydrates
correct_answer: enzymes
support: Chemical reactions constantly occur inside living things. Many of these reactions require catalysts so they will occur quickly enough to support life. Catalysts in living things are called enzymes. Enzymes may be extremely effective. A reaction that takes a split second to occur with an enzyme might take many years without it!.