Answer:
(C) damaging I think but not sure
<span>The spicules have an important purpose for loosely constructed animal such as sponge. First of all, spicules give structure which is vital due to loose construction. Secondly, it protects from predators. This is similar to porcupine quills in serving to protect.</span>
They lower the activation energy. The energy needed for a reaction to occur.
<span>ANSWER: lowering the amount of energy required.
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BTW. The enzyme is a ferment conducting chemical reactions in living organisms. Each enzyme catalyzes a chemical reaction strictly defined for a specific substrate and conditions.