Given a scientific question, generate a correct answer to it.
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Question: The four major classes of biological macromolecules include carbohydrates, lipids, proteins, and what else?

Answer: nucleic acids

Question: What control reproductive cycles, which are in turn regulated by environmental cues?

Answer: hormones

Question: What does the decomposition of dead organisms and organic waste release into the atmosphere, soil, or ocean?

Answer:
carbon