4317
Unlike the Ziegler-Natta process , which aims to produce very long polymers , the oligomer stops growing after addition of 1 - 10 repeating units of ethylene .
 Ziegler-Natta
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Ziegler-Natta