11995
Current alternative approaches to in vivo animal models involve use of a plethora of systems ranging from very simple models using human cells ( e . g . bronchial epithelial cells and fibroblasts ) in mono - or co - culture , whole tissue explants ( biopsies , muscle strips , bronchial rings ) through to in vivo studies in human volunteers .
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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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