1 VGA - VGA is an analog output, and was most common in the CRT-era of computer displays. It has largely been phased out of any recent hardware, but you may encounter it with older computers or CRT monitors.  DisplayPort - This is a digital connection, similar to HDMI.
There is evidence that iron was known from before 5000 BCE. The oldest known iron objects used by humans are some beads of meteoric iron, made in Egypt in about 4000 BCE. The discovery of smelting around 3000 BCE led to the start of the iron age around 1200 BCE and the prominent use of iron for tools and weapons.
Ironworking had evolved in East Africa before the rise of the city states. They improved the process and produced iron objects for trade as well as local use. Archaeology studies provide evidence that the city states carried on a flourishing long distance trade with Persia, India, and China.