What type of training aid includes physical materials such as models or artifacts?

The correct answer, which refers to the type of training aid that includes physical materials such as models or artifacts, is realia. Realia encompasses tangible items that provide learners with a concrete understanding of concepts, making lessons more engaging and effective. By integrating real-world objects into training, instructors can enhance comprehension and retention, allowing students to interact with the materials directly.

While software often refers to tools or applications used for training, and hardware relates to the physical technology used to support learning, neither directly includes physical materials like models or artifacts. Field trips, although experiential and valuable for learning, do not fall under the category of training aids that provide in-class tactile interaction with physical materials. Thus, realia is the most appropriate term for physical materials used in training environments.