What is the organisms that are mostly single-celles but some are multicellular.some like protozoans animal like.somelike algae plantlike called?

The organisms you are referring to are known as protists. They are primarily single-celled but can also be multicellular, and they display a diverse range of characteristics. Some protists, like protozoans, exhibit animal-like traits, while others, like algae, have plant-like properties. Protists belong to the kingdom Protista and play essential roles in various ecosystems.