Why is it easier to see the onion cells after they are stained with mythelene blue?

Staining onion cells with methylene blue enhances visibility because the dye binds to cellular components, particularly nucleic acids and proteins, providing contrast against the transparent background of the cells. This increased contrast makes structures like the cell wall and nucleus more discernible under a microscope. Additionally, the stain helps to highlight cellular details that would otherwise be difficult to observe in unstained preparations.