CellsThe cell is the basic unit of structure and function of a living thing.
TissuesTissues are made of a group of similar cells that work together to do a specific job in the body..
OrgansOrgans are made up of two or more tissues that work together to do a specific job.
Organ systemsAn organ system is a group of organs working together to perform particular jobs.
OrganismsSum of all cells, tissues, organs and organ systems makes an organism. An organisms is made when a group of organ systems work together.