29594
A total of 40 male Wistar Albino rats were divided into five groups : control , group I ( 3 weeks , 8 mg / kg ) , group II ( 6 weeks , 8 mg / kg ) , group III ( 3 weeks , 16 mg / kg ) , and group IV ( 6 weeks , 16 mg / kg ) .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
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