Which characteristic of effective teaching involves clearly communicating what action must be performed and how it must be performed?

In the context of effective teaching, the characteristic that involves clearly communicating what action must be performed and how it must be performed is communication. Effective communication is essential for instructors to convey their message, instructions, and expectations to students. It ensures that learners understand both the content and the processes involved, which is critical in a practical training environment, such as firefighting.

When an instructor communicates well, they can articulate complex ideas in a straightforward manner, making it easier for students to grasp the concepts being taught. This includes providing clear directions, using appropriate terminology, and checking for understanding. Overall, strong communication skills facilitate a more efficient learning environment and enhance students' ability to execute tasks correctly.

While motivation, organization, and clarity are also important aspects of teaching, they do not specifically address the necessity of transmitting information in a way that is easily understood and actionable, which is the core element highlighted in the question. Thus, communication stands out as the key characteristic in ensuring that students know exactly what is expected of them and how to achieve it.