Final answer:
Jenny should use high contrast text colors such as white or light shades for readability on dark backgrounds and a darker text color for labeling a lighter image like the sun.
Step-by-step explanation:
To make the content readable on a dark background on her slide, Jenny should use a high contrast text color like white or a light shade of yellow or blue that stands out against the backdrop. This will ensure that the text is easy to read against the dark background. For labeling the sun, which is likely to be a brighter element on the slide, Jenny could use a darker text color to create a contrast against the lighter image of the sun itself.
Visual contrast is crucial in presentation design to enhance readability and viewer engagement. In examples like a table with a dark blue header and white font or images set against a black background in a photo essay, the use of contrasting colors makes the information clear and allows for a better visual flow.