Final answer:
Positioning the character center stage and using lighting are two effects that would best emphasize a single character on a crowded stage.
Step-by-step explanation:
Two effects that would best emphasize a single character on a crowded stage are:
- Positioning the character center stage
- Using lighting to highlight the character
When a director wants to draw attention to a specific character, placing them center stage ensures that they are in a prominent position and easily visible to the audience. Lighting can also be used to create focus by illuminating the character while keeping the rest of the stage in a lower intensity. These two effects work together to highlight the character and make them stand out from the crowd.