18721
The problem of insufficient oxygen supply as the underlying cause for testicular impairment has received relatively little attention in toxicology , mainly because blood oxygen content is generally not measured in these animal experiments .
 Chemical: oxygen; Chemical: oxygen
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: oxygen; Chemical: oxygen