To act in response
reciprocate, respond, answer, counter, reply, behave, give back, act; see also answer 1.
To feel in response
be affected, respond, take, be struck, be impressed, be moved, be involved, find, catch the infection*, catch the flame*; see also feel 2.
"react." YourDictionary, n.d. Web. 20 May 2018. <http://thesaurus.yourdictionary.com/REACT>.
react. (n.d.). Retrieved May 20th, 2018, from http://thesaurus.yourdictionary.com/REACT
To act in return to something, as a stimulus:
To present with a specified reaction: