how do algae differ from protozoa?

Answer 1

Algae are vegetative. Protozoa are animal.

Answer 2

Protozoa eat algae. Algae need the sun to grow food with the chlorophyll

Answer 3

There is no absolute way to separate them. Typically algae carry on photosynthesis, have a cell wall, and have no means of locomotion. Typically protozoa have organelles of locomotion (except Sporozoa), are not photosynthetic, and have only a flexible cell membrane, not a cell wall. However, there are many intermediate forms, like Euglena which has no cell wall but is photosynthetic and has a flagellum for locomotion.