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Additive manufacturing technologies enable various possibilities to create and modify the material composition and structure on a local level , but are often prone to undesired defects and inhomogeneities .
 Additive manufacturing, material, composition, structure, defects
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
Answer:
 Additive manufacturing, material, composition, structure, defects