What is the relationship between eurozone and euro in the context of the input sentence. Choose an answer from: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

The euro edged down against the dollar after Athens failed to service its debt to the International Monetary Fund, and analysts warned of continued uncertainty, even after Greeks vote in a weekend referendum, which is effectively a poll on eurozone membership.

Answer: currency