Whch of the following was not an important part of early civilization? either a religion, cities, fancy clothing or big buildings or monuments

Religion- they definitely had it, even before civilisations people most likely had some beliefs

cities - yes, they did, I believe that we actually define "civilisation" by there being urban centers

fancy clothing: well, it depends what "fancy" means: but some form of decoration in clothing was present very early.

I would say that big buildings are a good in the beginning civilisations probably had one-or two- stories buildings

  Monuments: I think those actually were important (though not as big as today: for example even very ancient American organisations had stellae, a sort of minument.

Complementary goods. they go together, thats why one price increase and the others demand increases