Under president obama, there are about 500 members of the who serve as close, personal advisers to the president and are not subject to senate confirmation. white house staff executive office of the president cabinet council of presidential advisors

White House Staff

I recall this being on a quiz in class. Honesty it feels like a few other things can fit there but this is what we were told was right.

for many centuries there were important factors which the economies of the muslim empires developed increasingly. they applied economic procedures in production, investment, finance, taxation and property. they used to tax certain goods (for example: harvest), they charged interest on money lent, they signed contracts with merchants; they relied on a common currency, and they used checks as well as promissory notes. with the money collected by means of taxation, the government provided the needy with an income. in addition, trading networks covered huge distances, so far regions started to have contact and exchange goods. this trade network covered areas of asia, africa and europe.