Very long sentence in biography (4)
I believe the answer is:
life
This clue is a double definition.
'very long sentence' is the first definition.
'biography' is the second definition.
(I've seen this before)
'in' acts as a link.
(Other definitions for life that I've seen before include "Baffin oiler (anag) - 7 film" , "Maximum stretch?" , "and 12 Down: Biology, medicine, etc" , "Animation" , "'While there's .... there's hope'" .)