Wow, talk about your wide open questions! Arguably, the single greatest 'invention' is language. It allows us to discuss all the other inventions. Some people can argue that language is not an invention, but rather an extension of human's natural abilities. You could argue that the scientific method is also important. Without the requisite curiosity that is the hallmark of the scientific method, humans would still be mindlessly picking navel lint from their collective bellybuttons. Of course, with language, we could at least discuss the texture of said lint.
musical instruments...where would we be without music?
Central product
This is an opinion question which has been argued over a lot. Some think it's the wheel, others say something medicinal.
sky scraper
chopsticks Chinese accents the stuff that says made in china on it and china
the wheel.
The wheel
musical instruments...where would we be without music?
Everything apple
The wheel.
In my opinion, electricity
Iphone 5
electricity
plow
The telescope.
mongorians
Because it made transport easier.