Which act of the u. s. congress converted the loosely confederated national military establishment into an executive department, renamed the department of defense (dod); reduced the departments of the army, navy, and air force to military departments within dod; and added a chairman to preside over the joint chiefs of staff without any further substantive powers

The name of that act of the U.S. Congress is

National Security Act of 1947.

Explanation:

The Act is called ;Reorganization Act of 1947

Explanation:

The act created the position of secretary of defense to look over the nation's military services. It terminate the Departments of the Navy, Army and created the War Department.

would it be plagiarism to copy and paste off of here? ?