Final answer:
Effective visual aids should be integrated, c) included for a purpose, uncluttered, and not skewed to ensure information is presented accurately and clearly.
Step-by-step explanation:
The most effective visual aids are not skewed. When creating visual aids such as charts, graphs, or images, they should present information in an unbiased and accurate manner. Visual aids should be integrated into the text, be included for a purpose, and remain uncluttered to effectively support the content and enhance understanding. Distorted or misleading visuals can lead to misinterpretation of information and should therefore be avoided.