How do euglenoids show difficulty of classifying protists as plants or animals?

Euglenoids, such as Euglena, exhibit characteristics of both plants and animals, complicating their classification within the protist kingdom. They possess chloroplasts and can perform photosynthesis like plants, yet they also exhibit motility through flagella and can consume organic matter when light is unavailable, resembling animal behavior. This duality highlights the challenges of categorizing protists, as many share traits across traditional plant and animal classifications. Ultimately, euglenoids exemplify the complexity and diversity within protists, blurring the lines between these two biological kingdoms.