Memory aids that involve the use of vivid imagery and clever ways of organizing
material are called
a. semantic techniques.
b. iconic traces.
c. organizational cues.
d. mnemonic devices.
e. flashbulb memories.

Mnemonic devices

Explanation:

Mnemonic devices are creative tools designed to help you remember things.

A simple, (but very effective anyway) mnemonic can be seen in the image attached below. In order to remember the planets of the solar system, their tyoplogy, and their order, a young kid in elementary school could simply write each planet's name on his fingers, and the typologies on his palms.

Note that the use of vivid imagery and clever ways of organization can be seen in this example.

in 342 bc j._c. egypt fell into the hands of the persians, under the reign of nectanebo ii

greek city-states unite in a revolt against the persian empire at the beginning of the fifth century bc. j.-c  

from the year 660 or 659 bc ad, cyrus preached the revolt against the medes to deliver the persians.