(finance) observing something's development first instead of acting immediately

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

chemical reaction / reaction, response / feedback

to react chemically / to respond, to react / be responsive, be sensitive

he; boyfriend

transplant rejection / allergic reaction

chain reaction (series of events) / chain reaction (type of nuclear reaction)

everything

(chemistry) a chemical reaction