Conjecture: Why do you think there are places that stay near an average height all the time? (Ripple tank gizmo)

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 : )

option number c is the right answer.

find the sum of the two horizontal vectors and the sum of the two vertical vectors

isoceles right angled triangle