17048
Biological processes bringing about these responses are respectively driven by the circadian timing system , a complex of biological oscillators entrained to the environmental light / dark cycle , and by regulatory and metabolic networks that precisely direct the body ' s adjustments to variations of external conditions and internal milieu .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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