Read the definition. the result produced from an event which term is defined?

The answer is "causes" because it deals with the products of an event

The last of a series of causes, although not necessarily the proximate cause,of an effect or result... Furthermore,the effect or result produced by the proximate cause would have occurred even if there would be a subsequent action,event or force that contributed to the eventual effect or result

Whitman wanted to express that America is a country constituted by several parts that make a whole that works well. Each individual of the country doing their part is what forms the nation.

A choir is a group of people in which each one has a part to sing that might not be special on their own but form a harmony when they are sung together,