Adding heavy elements to IVs helps (7)
I believe the answer is:
favours
'helps' is the definition.
The answer and definition can be both acts as well as being plural nouns.
Perhaps they are linked in a way I don't understand?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for favours that I've seen before include "indications of support" , "Supports or prefers one thing or person over another" , "Approves" , "Good turns" .)