Final answer:
The amoeba is a single-celled organism that belongs to the kingdom Protista.
Step-by-step explanation:
The correct answer to the question is a) Protist. The amoeba is a single-celled organism that belongs to the kingdom Protista. Protists are a group of eukaryotic microorganisms that can be either unicellular or multicellular. Amoebas are characterized by their ability to constantly change shape through the process of cytoplasmic streaming, and they move by extending their pseudopods.
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