[Solved] Which of the following was LEAST likely to be the focus of study for the functionalists? A) mental testing B) development in children C) sensation and perception D) the effectiveness of educational practices GUI: Graphical User Interface, a human-computer interface that allows users to interact with electronic devices using graphical icons and visual indicators. Visible Objects: Items or entities that can be seen by the naked eye under normal lighting conditions. Complex Commands: Advanced or intricate instructions that are given to computers or software to perform specific operations. Open Source Software: Software with source code that anyone can inspect, modify, and enhance because it is publicly accessible.