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.""

one of the negative side effects were the economic losses the events of september 11th caused. many, many people lost their jobs as a result of a downturn in the economy after the terrorist attacks.

a. factors that are used to make goods and services