an effort, an endeavor

to endeavor, to make an effort

needed, necessary

need, necessity

solution, settlement / (music) Progression from dissonance to consonance; a chord to which such progression is made; resolution

(transitive) solve, resolve, settle (a problem, a trouble, a criminal case) / (intransitive) be solved, be settled / (intransitive) can be solved; be soluble

minimum, smallest, least

question, problem on homework etc. / a question; a matter (of time etc.) / a problem (something that needs to be dealt with); a trouble / an issue; a matter

necessity (quality or state of being necessary, unavoidable, or absolutely requisite)

unnecessary