If you travel 5 miles north then turn and travel 5 miles south, you are now miles from where you started.

If you travel 5 miles north then turn and travel 5 miles south, you are now 0 miles from where you started.

Explanation: Think of it as going forward and backwards you will be back where you started.

c. convergent boundary.

explanation:

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 : )