10476
Should the polymerase progress further towards the uracil , for example , to position uracil only two bases in front of the junction , 3 ' - 5 ' proof - reading exonuclease activity becomes stimulated , trimming the primer and re - setting uracil to the + 4 position .
 Chemical: uracil; Chemical: uracil; Chemical: uracil
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: uracil; Chemical: uracil; Chemical: uracil