I forget where I saw this, but a publication at the change of the last century... 1899... indicated the most influential invention of the previous century was... believe it or not... the "safety match". This had a huge impact on the people of the late 1800's and early 1900's. Today we are so focused on things like communication and information we forget what would have mattered back then. You really need to study history to get a perspective about the present and the future. It has been obvious to me for a long time that access to information is our current paradigm shift. We will never go back to the old days when information and communication was only available to a fortunate few.
Written language is the clear winner in my book. This allowed information to be communicated & stored outside one brain by others, even if the others were located far away in time or distance. This made cumulative knowledge possible, and technological advances took off. Individuals today are no more nor less innovative than cavemen. Written language just allows modern people to leverage all of humanity's brains.
Who said we're more innovative than cavemen?
Could you survive with no farm, no home, no car, no technology?
The survival skills of the cavemen was astounding! To be able to survive and thrive in such a primitive environment.
Now if we're talking about society - then that is where the technological advancements made huge progress. Tech progress is a group, team, and society effort. Education of children and support for that from adults - this is why progress was made.
Very difficult to say :)
...but as your question is which one among the listed enabled us to become more organized civilization, I think my vote will be for the first one: "Language/communication (writing numeral, symbols etc.)"
You're right, I worded that badly. What I meant was, which category of innovations enabled us to make the leap into more organized civilization. We certainly didn't invent language--however, we did come up with symbols to communicate our thoughts. Though I agree with David--lets vote for beer and be done with it!
Then by the same reasoning of the first post, apes, whales and even birds and ants communicate, albeit at a lower level than humans (though even that is open to question sometimes).
I don't reckon any of the others cut it. That only leaves Beer....