67580
The products of this process ( called secular evolution ) are often observed in such galaxies ; both spiral disks and galactic bars can result from secular evolution of galaxy disks .
 astronomical object: spiral disks; astronomical object: galactic bars
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: spiral disks, galactic bars 
Answer:
 astronomical object: spiral disks; astronomical object: galactic bars