Animals are multicellular eukaryotic organisms in the biological kingdom Animalia.
With few exceptions, animals consume organic material, breathe oxygen, are able to move, reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development.
Animals range in size from 8.5 millionths of a metre to 33.6 metres (110 ft) long and have complex interactions with each other and their environments, forming intricate food webs.
Animals may be listed or indexed by many criteria, including taxonomy, status as endangered species, their geographical location, and their portrayal and/or naming in human culture.
Basal animals are delineated according to the following cladogram: Choanoflagellata Porifera Ctenophora Placozoa Cnidaria Xenacoelomorpha Nephrozoa Animals: Porifera, Diploblasts Diploblasts: Ctenophora, ParaHoxozoa ParaHoxozoa: Placozoa, Cnidaria, Bilateria/Triploblast Bilateria: Xenacoelomorpha, Nephrozoa Nephrozoa: Protostomes, Deuterostomes