511
for decades , most of the nation 's renewable power has come from dams , which supplied cheap electricity without requiring fossil fuels .
 cause effect: power, dams
Given options, please tell me the relationships of all the listed entity pairs.Output format is "relation1: word1, word2; relation2: word3, word4". 
Option: component whole, NA, instrument agency, member collection, cause effect, entity destination, content container, message topic, product producer, entity origin 
Text: {0} 
 Entity Pairs:  power, dams 
Answer:
 cause effect: power, dams