Students can process more information when _____ supplement a lecture.

The correct answer is visual aids, as they play a significant role in enhancing the learning experience during a lecture. Visual aids such as slides, videos, diagrams, and charts help to illustrate key concepts and reinforce the spoken information. This multimodal approach caters to various learning styles, making it easier for students to comprehend and retain information.

Visual aids can simplify complex ideas, making them more accessible. When students can see representations of the material being discussed, it allows them to create mental connections and enhances their overall understanding.

On the other hand, tests, pop quizzes, and reading assignments, while useful educational tools, do not directly supplement a lecture in the same way that visual aids do. Tests and quizzes often assess knowledge rather than enhance it during delivery, and reading assignments typically serve as preparatory or follow-up work rather than immediate reinforcement during a lecture.