Animalia, the animal kingdom, is a very diverse group of organisms. With all this diversity, what is it that sets them apart from other groups, and yet have so much in common?
The following are the main qualifications.
1) they are multicellular.
2) most include a spherical embryonic stage called a blastula.
3) they all, at some lifestage, ingest their food for internal digestion. Their food mostly consists of other organisms.
4) they all need oxygen.
5) almost all are able to move about during some stage of their life.