Motion system
Have an active form of locomotor muscles and have limbs in
pairs.
Circulatory system
Heart grow well, with the ventricles (booth space) and
atrium (porch), there are bears two, three or four.
Digestive system
The digestive system is perfect, extending from the mouth to
the anus at the base of the spine. Generally have teeth, tongue, and two pairs
of jaws, except on Agnatha (Cyclostomata). There are liver and pancreas.
Respiratory system
Gills in vertebrates that live in the water, and lung in
vertebrates that live on land.
Excretory system
Has a pair of kidneys. Some are having bladder.
The senses and the nervous system
Have a central nervous system such as brain and spinal cord.
Generally have a pair of eyes, ears, and have hormonal glands.
Reproductive system
Reproductive pairs, except at Aves females only have one
ovary left. Separate sex or hermaphrodite in larvae and as adults as animal
Diesis (married two). External or internal fertilization. There are ovipar,
vivipar, or ovovivipar.