Enzymes are required for most chemical reactions in living cells because..

Enzymes are required for most chemical reactions in living cells because these reactions need to happen very quickly and need a catalyst. Enzymes are catalysts for chemical reactions in living things. Enzymes, being a catalyst, decreases the activation energy needed to start a chemical  reaction and, as a result, also increases the rate of the chemical reaction.

producers: apple trees, potatoes, carrots, grains, acorns, cabbage, grass, corn, lettuce

consumers: deer, mice, rabbits, chickens, squirrels, horses, worms, cows

predators: eagles, frogs, wolves, owls