12015
O ( 2 ) regulates various aspects of cellular biology and , in vivo , MSC are exposed to different O ( 2 ) concentrations spanning from very low tension in the bone marrow niche , to higher amounts in wounds .
 Chemical: O ( 2 ); Chemical: O ( 2 )
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: O ( 2 ); Chemical: O ( 2 )