Travel and easy access to drinking water.
Answer:
The first stage was military unification, which was carried out with the Northern Expedition. The second was "political tutelage" which was a provisional ..
The answer I believe is B !
Over the years of history, there have been several technological inventions that have improved the value of Human life. Some of these inventions dating as far back as 450CE are still in Use to this day.
Below you can read more about Technological inventions between 450CE and 1600CE that are still impactful to this day.
<h3>Technological inventions between 450CE and 1600CE</h3>
PAPER MONEY
Paper money is one of the most important inventions that is still useful to this that. The earliest known use of Paper money was during the Tang Dynasty.
This invention came handy at a time carrying large sums of money was difficult and there was shortage of supply of metal.
Also people needed a central value to carry out Trade.
WINDMILLS
Windmill is yet another invention withing the time frame that is still relevant to this day.
Windmill involves the use of wind to create energy. The first windmills were used to mill grain. The Persians were known to be the first to invent a functional windmill in the 9th Century and this had 'sails' that rotated horizontally instead of vertically as we typically see today.
Learn more about technological inventions at brainly.com/question/24839581
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