Which of the following aspects of vocalization is Peggy using during her presentation?

Volume pertains to the loudness or softness of one's voice. While adjusting volume can be effective in capturing attention, it does not specifically convey emotion or emphasis in the same way that inflection does. Therefore, simply changing volume alone does not highlight the nuances of her presentation as inflection does.

Pauses are strategic breaks in speech that can enhance clarity and allow the audience to absorb information. However, while pauses can be impactful, they do not inherently involve variations in pitch or tone that characterize inflection. Thus, they serve a different purpose in vocalization than what Peggy is employing.

Rate refers to the speed at which someone speaks. Although pacing can affect the delivery of a presentation, it does not involve the tonal variations that inflection provides. The rate of speech is important for clarity but does not serve the same function as inflection in engaging the audience's attention.