Which of the following nonverbal behaviors is essential for an effective presentation in public speaking?

Maintaining eye contact with the audience is a crucial nonverbal behavior for an effective presentation in public speaking. Eye contact helps establish a connection between the speaker and the audience, fostering engagement and rapport. It signals confidence and sincerity, encouraging the audience to pay attention and feel involved in the presentation. Additionally, continuous eye contact can help the speaker gauge the audience's reactions, allowing for adjustments in tone, pace, or content based on their level of interest and responsiveness.

In contrast, excessive smiling might distract from the message if not appropriately timed with the content being delivered. Reducing bodily movement to a minimum can lead to a presentation that feels static and disengaged; some movement can enhance communication when used appropriately. Avoiding glasses is not relevant to presentation effectiveness; many speakers wear glasses without any negative impact on their ability to connect with the audience. Thus, maintaining eye contact stands out as the key nonverbal behavior that enhances the effectiveness of public speaking.