Which of the following is a physical element that carries a message between a sender and a receiver?

A channel is the physical medium through which a message is transmitted from a sender to a receiver. This can include various forms of communication, such as cables, wires, or wireless signals. Understanding this concept is crucial in health informatics, where the integrity and reliability of data transmission are essential for effective communication between healthcare providers and systems.

The other options do not serve this specific purpose. A clicker typically refers to a device used for interactive polling or feedback but does not represent a conveyance medium for messages. A clinical application refers to software or tools used in healthcare settings to support clinical activities but does not function as a physical medium. A charge description master is a catalog of services and their respective billing codes in healthcare, which is also not related to the physical transmission of messages.