Sphere of activity offering a new life to hundreds (5)
I believe the answer is:
field
'sphere of activity' is the definition.
'field' can be an answer for 'sphere' (synonyms). I am not sure about the 'of activity' bit.
'a new life to hundreds' is the wordplay.
'a new' indicates anagramming the letters.
'to hundreds' becomes 'd' (I've seen this in other clues).
'life' anagrammed gives 'fiel'.
'fiel'+'d'='FIELD'
'offering' acts as a link.
Can you help me to learn more?
(Other definitions for field that I've seen before include "Area of farm land" , "Branch of study" , "Domain" , "his nocturnes, perhaps?" , "Area of farmland" .)