The kingdom Animalia belongs to the domain Eukarya.
Explanation: The domain Eukarya encompasses all organisms with complex cells that contain a nucleus. This includes not only animals but also plants, fungi, and protists. Members of the Animalia kingdom are multicellular, typically capable of movement, and rely on other organisms for food. The classification into domains helps scientists understand the relationships and characteristics of different life forms, and recognizing that Animalia falls under Eukarya is crucial for biological taxonomy.