Coming up with memory tricks such as roy g. biv for the visible spectrum of colors and homesfor michigan's great lakes are types of

a. mnemonics.
b. repeated testing.
c. spaced practice.
d. recency effects.

A. Mnemonics.

A mnemonic is a device used to memorize information by reducing the elements of a topic to it's key elements.

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.