Is Plasmodium a bacteria. Why?
No, Plasmodium is actually a protozoan—that is, a single-celled organism that is usually microscopic and belongs to the Domain Eukaryota (which also includes all plants and animals, but excludes bacteria and archaea). More specifically, Plasmodium belongs to the Apicomplexa group of protozoans, which are characterised as being parasites of animals, and possessing several unique characteristics, such as an apical complex structure used for invading host cells, and from which the group derives its name.
Protozoans differ from bacteria in terms of evolutionary history as well as a number of key characteristics. For example, protozoans, like all eukaryotes, possess a membrane-bound nucleus and organelles, neither of which are seen in bacteria. Bacteria, moreover, can produce their own food (they are autotrophic), whereas protozoans tend to be heterotrophic and rely on other organisms for food.