I wonder what do you call two things that are related to one another in such a close way that each one “needs” the others in order to exist and none of them can last without the other one? I know just two adjectives and their associated verbs. Whilst dictionaries couldn’t help me much, I wonder which choice doesn’t work in this sense:
1- They are interdependent.
2- They interdepend.
3- They are correlative.
4- They correlate.
I would appreciate it if you could let me know about even a bettrthere option if exists.
If either of the ‘two things’ truly need each other, then correlation is not the right word to use – two completely unrelated, co-incidentaly variables may correlate completely, see this example if it helps.
Interdependence/Interdependant is probably the best choice here, but you may also want to look at symbiosis (mainly for organisms) or collaboration (mainly for humans)