Algae and Protozoa are two examples of organisms that belong to the same kingdom. Both belong to the kingdom Protista. And since they are from the same kingdom, they are very similar based on some properties that are common between them. They are eukaryotic organisms because they cannot be regarded as an animal, plants, or fungus. Algae are photosynthetic organisms, and as a result, they can produce their own food. Protozoa, on the other hand, are nonphotosynthetic organisms or animal-like protists that feed only on small organisms.
They move only by using pseudopods, cilia, or flagella. Protozoa are shapeless organisms, and they are unicellular organisms, and that's why before you can have a good look at them, you need a microscope. Algae, on the other hand, look like green, and that's why there is the presence of chlorophyll in their cells. They are mostly seen and found floating on water.