The obligations of a variety of endless studies (6)
I believe the answer is:
duties
'the obligations' is the definition.
('duty' can be a synonym of 'obligation')
'a variety of endless studies' is the wordplay.
'a variety of' is an anagram indicator.
'endless' means to remove the last letter.
'studies' with its last letter removed is 'studie'.
'studie' is an anagram of 'DUTIES'.
'of' is the link.
(Other definitions for duties that I've seen before include "Taxes or responsibilities" , "Moral or legal obligations" , "Tasks or tariffs" , "Obligations and responsiblities" , "Obligations or taxes" .)