Are humans animals?
animals are "metazoa": muilticellular eukaryote creatures with connective tissues. Bacteria and archea are not animals as they are single-celled. Furthermore, animals must be heterotrophic, which means they don't use carbon as part of their digestion process (this excludes plants). Fungi are also heterotrophic, but there's a further distinguishing feature of metazoa: they don't have cell walls. Finally, a cherry on top, animals are mobile: they can move around. I'm not sure how sponges fit into this, so maybe they're an exception, but their look-alike ancestors are also one of the first animals.
Humans conform to all of the classifications of metazoa, so yes, they are animals.