Which is a key feature of educational Google Hangouts?

The key feature of educational Google Hangouts is the engagement tools for student interaction. These tools are designed to enhance communication and collaboration among participants during online classes or study sessions. Features such as chat, Q&A, and polls allow educators to foster interaction and maintain student engagement, which are critical components of effective online learning.

In an educational setting, facilitating active participation is vital for students' understanding and retention of information. The ability for students to ask questions in real-time, provide feedback, and engage in discussions makes the learning experience more interactive and dynamic. These engagement tools help to replicate the interactivity of a physical classroom, making online education more effective.

On the other hand, aspects like live streaming of personal events do not focus on the educational context and would not be suitable as a key feature. Automatic recording may be useful in some contexts, but it doesn't specifically enhance interactive learning during the session. Lastly, while the pre-scheduling feature can be convenient, it is not a defining characteristic of the educational purpose of Google Hangouts in comparison to the importance of engagement tools.