3647
As stated , while Bronze Age economy was based on the exploitation and exportation of mineral local resources , tin and copper and on mass production and long range distribution of prestige items , Iron Age economy was based on an economy of necessity goods , as most items and productions were obtained " in situ " , or interchanged thought short range commerce .
 time: Bronze Age; time: Iron Age
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
 Entities: Bronze Age, Iron Age 
Answer:
 time: Bronze Age; time: Iron Age