an organism has the following features: multicellular; cells with true nuclei; able to move using a muscular tail; brain. To which kingdom would this organism belon?

Considering the features listed about the organism, it belongs to the Animalia kingdom because the main characteristic is to have a brain, which other species in the other kingdoms do not have; also, animals are the only species that have muscles compared to the other kingdoms, and each cell in their body has a true nuclei as its type is 'Eukaryotic:' a cell that contains a nucleus within membranes, so animals are mutlicellular organism.