Which aspect is vital for effective online classes during a synchronous learning session?

For effective online classes during a synchronous learning session, simultaneous interaction among students and instructors is vital. This interaction fosters a sense of community and engagement, which is crucial for maintaining students' attention and encouraging participation. When students and instructors can communicate in real-time, it allows for immediate feedback, clarification of concepts, and dynamic discussion. This interactive component helps to replicate the immediacy of in-person classes, leading to a richer learning experience and improved understanding of the material.

In contrast, flexibility in attendance without participation diminishes the interactive quality that a synchronous session offers. While pre-recorded materials can be useful, they do not provide the same level of engagement that live interaction encourages. Lastly, requiring in-person attendance is not practical or feasible for online learning environments, where the goal is to provide access regardless of location. Thus, the aspect of interactive engagement stands out as a cornerstone of effective synchronous online education.