Benjamin Zander's main goal in this video, The Transformative Power of Classical Music, is to show how much impact a piece of music can have on the mind. He makes the point that music is just frequency.
The use of slaves was reduced, because immigrants could fulfill the same roles as slaves in factories.
A.the lack of overall deposit
In Africa, a number of specialized occupations developed ,highly skilled metal smiths developed more effcient tool that increase agricultral produtivity. they also produce improved weapons ,which became important in the expansion of kingdoms.
