Nuclear power is the only energy source which gives off radiation.
a. true
b. false

i guess that visual aids present persuasive examples to what you are presenting, some factors would be theme (does it fit with the color, information, what you are presenting), size (can you see it, is it a big enough span of data/information), and overall look of the visual aid.

hope this : )

a longitudinal wave moves energy that is to the direction of the wave’s movement. - true