who appoints the head of the cabinet departments
Cabinet of the United States The heads of the executive departments and all other federal agency heads are nominated by the President and then presented to the Senate for confirmation or rejection by a simple majority (although before the use of the "nuclear option" during the 113th US Congress, they could have been blocked by filibuster, requiring cloture to be invoked by ​3⁄5 supermajority to further consideration). If approved, they receive their commission scroll, are sworn in and then begin their duties.
United States Department of Justice The department is headed by the United States Attorney General, who is nominated by the President and confirmed by the Senate and is a member of the Cabinet. The current Attorney General is Jeff Sessions.