In which kingdom would you classify algae and protozoa?

Algae and protozoa are classified in the kingdom Protista due to their unicellular or simple multicellular structures and their predominantly aquatic habitats. Protista serves as a diverse category that includes organisms that do not fit neatly into the other kingdoms like Animalia or Fungi. Algae, which can perform photosynthesis, are often plant-like, while protozoa are more animal-like and typically heterotrophic, meaning they obtain food by consuming other organisms. This kingdom acts as a catch-all for eukaryotic organisms that are not classified as plants, animals, or fungi, highlighting the complexity and diversity present within this group.