Final answer:
Advertising is conveyed through various mediums, is designed to persuade, and is typically paid for. The source of the message is usually required to be known for legal transparency.
Step-by-step explanation:
The aspects of advertising include that it is carried by some medium, such as television, radio, print, or online channels. Advertising is often a creative and argumentative form of communication designed to persuade or inform an audience, and while some opportunities exist for free exposure, such as media opportunities or public service announcements, most advertising is paid for and used to sell products or services. Contrary to one of the options provided, legally, the source of the message commonly must be known as to maintain transparency and trust with consumers.