14489
METHOD : Forty - five male Lister hooded rats were housed in groups of 3 - 4 ( n = 16 ) or singly ( n = 29 ) for 4 weeks immediately after weaning on postnatal day ( PND ) 22 - 24 .
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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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