55161
Although the candela is now defined in terms of the second ( an SI base unit ) and the watt ( a derived SI unit ) , the candela remains a base unit of the SI system , by definition .
 second
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 second