Given a scientific passage and an answer, generate a question for the given answer.

Q: Passage: Most chemical reactions in organisms take place in an environment that is mostly water. Answer: water

A: The environment where most chemical reactions in organisms takes place consists mostly of what?
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Q: Passage: Chemical reactions constantly occur inside the cells of living things. However, under the conditions inside cells, most biochemical reactions would occur too slowly to maintain life. That's where enzymes come in. Enzymes are catalysts in living things. Like other catalysts, they speed up chemical reactions. Enzymes are proteins that are synthesized in the cells that need them, based on instructions encoded in the cells' DNA. Answer: enzymes

A: What proteins synthesized in cells act as catalysts?
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Q: Passage: The amount of reactants and products do not have to be equal. However, after equilibrium is attained, the amounts of reactants and products will be constant. Answer: equilibrium

A:
In a chemical reaction, the amounts of reactants and products will be constant when what state is attained?
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