Phylum Vertebrata has the most complex animals.
complex animals have no back bones and simple animals have backbones
Glycogen is the complex carbohydrate used to store energy in animals.
Cells are so specialized to carry out all the complex functions in animals and plants.
There are quite a few animals that contain tissues but lack complex organs. One of these animals is the jellyfish.
complex animal have two stomachs
yes... $_$
The Life that animals have.
social animals
The Life that animals have.
arthropods
Digestion