Which document allowed the colonists to make treaties and establish a postal service

The Articles Of Confederation gave the united states the power to establish the U.S. postal service, as well as make treaties.

https://www.history.com/topics/early-us/articles-of-confederation

"But Congress would exercise considerable powers: it was given jurisdiction over foreign relations with the authority to make treaties and alliances; it could make war and peace, maintain an army and navy, coin money, establish a postal service, and manage Indian affairs; it could establish admiralty courts; and it ..."

https://www.monticello.org/site/research-and-collections/postal-service

"Benjamin Franklin was appointed as postmaster general. Despite a clause in the Articles of Confederation to establish a federal post office, Congress waited until October 18, 1782, to pass "An Ordinance for Regulating the Post-Office of the United States of America.""

the labor movement in the united states grew out of the need to protect the common interest of workers

for those in the industrial sector organized labor unions fought for better wages reasonable hours and safer working conditions

  in the 19th century trade unionism was mainly a movement of skilled workers.

hope this

answer:    

a.

explanation: