Responds (6)
'responds' is the definition.
('react' can be a synonym of 'respond')
This is the entire clue.
(Other definitions for reacts that I've seen before include "Acts in response to something" , "Retaliates" , "Responds to an impulse" , "Responds to stimulus (6)" .)
'responds' is the definition.
('answer' can be a synonym of 'respond')
This is all the clue.
(Other definitions for answers that I've seen before include "Rawness (anag)" , "keys" , "Returns" , "Responds" , "serves" .)