Which key document established USNORTHCOM as the combatant command assigned to defend the United States

Unified Command Plan, Joint Publication 3-28 and Joint Publication 3-26

Explanation:

United States Northern Command was established to provide command and to coordinate defense support of civil authorities and defends America's homeland. Classified documents such as Unified Command Plan, Joint Publication 3-28, and Joint Publication 3-26 are key documents that established USNORTHCOM as the combatant command assigned to defend the United States. These documents establish the missions, command responsibilities, and geographic areas of responsibility of United States Northern Command (USNORTHCOM).

a. the astrolabe could determine the correct latitudinal location of the ship

b) they want the land taken away from the wealthy landowners and given to peasants.