These organisms contain chloroplasts and perform photosynthesis. They produce a huge portion of the world's oxygen.
These are heterotrophs, meaning they have to "hunt" or consume other organisms for food.
The Protista kingdom is often called the "biological junk drawer." It’s a massive, diverse group of eukaryotes—organisms with complex cells—that simply don't fit into the categories of plants, animals, or fungi. Because they are so varied, the best way to understand them is to look at how they move and eat.