The blood<span>, which is now low in oxygen, is now collected in veins and travels to the right atrium and into the right ventricle. Now pulmonary circulation starts: The right ventricle pumps </span>blood<span> that carries little oxygen into the pulmonary artery, which branches off into smaller and smaller arteries and capillaries.
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Memory would be a good answer, but I'm quite uncertain :/
Answer:
Enzymes are biological catalysts. Catalysts lower the activation energy for reactions. The lower the activation energy for a reaction, the faster the rate. Thus enzymes speed up reactions by lowering activation energy.
