There are two sets of bones that make up the skull. The ______ bones surround the ______ which encloses the ______, and provides sites of attachment for head and neck muscles. The top part is called _____ or ________, the lower part forms the __________, which has three fossae called ________, _______,and ________ cranial fossa. The _______ bones form ______, and openings for ______ and _______ passage