847
As a result , beta - apo - 8 ' - carotenoic acid ethyl ester ( apo - EE ) was used as a reference standard in Experiments 4 to 6 .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
Answer:
 None