Animals kingdom of the world is divided into two sub-kingdoms :
						
                        1.	Unicellular animal
						2. Multi-cellular animal or Metazoans
                        Unicellular animals are kept in a single phylum Protozoa whereas multi- cellular animals are divided into 9 phylums.
                      
                        
                        » They are Unicellular.
                          » It's body is made of only one cell.
                          » There is one or more nuclei in its cytoplasm.
                          » It is parasitic and free living.
                          » All the metabolic activity (eating, digestion, respiration, excretion, reproduction) takes place in unicellular body.
                          » Respiration and excretion take place by diffusion.
                          Example - Amoeba, Euglena, Trypanosoma etc.
                          
                        
                        All animal of this group are found in marine water & bear pores in body.
					  » These are multi cellular animals but cells do not make regular tissues.
                      » Numerous pores known as ostia found on body wall.
                      » Skeleton is made up of minute calcareous or silicon spicules.
                      Example -Sycon, Sponge etc.
                        
                        » Coelenteron is present inside body.
                      » Animals are aquatic and diploblastic.
                      » 	Around the mouth some thread-like structure are found known as tentacles, which help in holding the food.
                      » Body radial symmetry.
                      » Specialized cnidoblast cell are found help in catching the food.
                      Example -  e-Hydra, Jellyfish, Sea Anemone etc.
                        
                       »	Its a Flat worm
                       »	Triploblastic and nobody cavity.
                       »	Dorso-ventraly flattened animal.
                       »	Alimentary canal with single opening, anus absent.
                       »	Excretion takes place by flame cells.
                       »	There is no skeleton, respiratory organ, circulatory system etc.
                       »	These are hermaphrodite animal.
                       Example - Planaria, Liver fluke, Tape worm etc.
                        
                        » Its a Round worm
						» Long, cylindrical, unsegmented worm.
						» Bilaterally symmetrical and triploblastic.
						» Alimentary canal is complete in which mouth and anus both are present.
						» There is no circulatory and respiratory systems but nervous system is developed.
						» Excretion takes place through Protonephridia.
						» They are unisexual.
						» Most form are parasitic but some are free living in soil and water.
                        Example - Round worm, like - Ascaris, Thread worm, Wuchereia etc.
                        1.	Enterobius	(pin worm/thread worm) - It is found mainly in the anus of child. Children feel itching and often vomits. Some children urinate on the bed at night.
                        2.	Filarial disease is caused by Wuchereia bancrofti.
                       
                        
                        
                        » It is Annulus body Bearing ring.
                      » Body is long, thin, soft and metamerically segmented.
                      » Locomotion takes place through Setae made up of Chitin.
                      » Alimentary canal is well developed.
                      » 	Normally respiration through skin, in some animals it takes place through gills.
                      » Nervous system is normal and blood is red.
                      » Excretion by nephridia.
                      » True coelom is present.
                      » Both unisexual and bisexual.
                      Example -Earthworm, Nereis, Leech etc.
                        
                        » It is Jointed leg.
                          » 	Body is divided into three parts - Head, Thorax and Abdomen.
                          » Body is covered with a thick chitinous exoskeleton.
                          » Circulatory system is open type.
                          » Its body cavities are called haemocoel.
                          » Tracheai, book lungs, body surface are respiratory	organ.
                          » These are mainly unisexual and fertilization takes	place inside the body.
                          Example - Cockroach, prawn, crab, bug fly, mosquito, bees etc.
                          1.	There	are six feet and four wings in insects. 
                          2.	There are 13 chamber in the Cockroach's heart. 
                          3.	Ant is a social animal which reflects labour division.
                          4.	Termite is also a social animal which lives in colony.
                          5.	The main excretory organ of insects are malpighian tubules.
                          
                        
                        » It is Soft bodies animal.
                      » All the animals in this group are marine.
                      » Water vascular system is present.
                      » There is Tube feet for locomotion, taking food which works as sensation organ.
                      » Brain is not developed in nervous system.
                      » There is a special capacity of regeneration.
                      Example  -Star fish, Sea urchin, Sea cucumber, Brittle stars etc.
                      
                      1. The function of the Aristotle lantern is to chew the food.
                      2. It is found in sea urchin.