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Support structures and materials are indispensable components in many Additive Manufacturing ( AM ) systems in order to fabricate complex 3D structures .
 engineering feature: Support structures; concept or principle: materials; machine or equipment: components; manufacturing process: Additive Manufacturing; manufacturing process: AM; manufacturing process: fabricate; concept or principle: 3D structures
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: 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} 
 Entities: Support structures, materials, components, Additive Manufacturing, AM, fabricate, 3D structures 
Answer:
 engineering feature: Support structures; concept or principle: materials; machine or equipment: components; manufacturing process: Additive Manufacturing; manufacturing process: AM; manufacturing process: fabricate; concept or principle: 3D structures