Please forgive me, I don’t want to come over a an awkward pedantic git but.....
Without chemical, I suggest agitation is of no use so chemical must be of more importance than agitation alone.
Without chemical I suggest time is of no relevance, if no pre spray is applied what are we waiting for? So chemical must be important than time alone.
Without flow then time, agitation, chemical and temperature is of no use so logically flow is the only thing we can use to clean on its own so it must be the most important of all four but I don’t recommend using that as a method of cleaning!
To clean successfully we need a combination of all four. It’s true we can sometimes clean without dwell time, agitation or heat so I think the minimum we need is chemical and flow. Apologies if I’ve missed the point of this poll, but I can’t meaningfully vote.