Yes, Oman is developed and improving all the time.
Ghana is at this current point in time an LEDC (less economically developed country) so it is not that developed, no.
babylonians
The Flute was developed over a long period of time-the MiddleAges! It was developed so the player could have a wider range of melody.
Ben Albotri
its magical
I believe the first well-developed system of time measurement was created by the Babylonians, although I don't know when that was exactly. (Isn't that ironic?)
simple
it has just changed
sorry
I believe it is the 1990s.
sorry