levees of organization
Cells is :
The cell is the basic unit of structure and function of a living thing.
Tissues are made of a group of similar cells that work together to do a specific job in the body.
Organs are made up of two or more tissues that work together to do a specific job.
Organ systems is :
An organ system is a group of organs working together to perform particular jobs.Example: Human organ systems include circulatory, reproductive, digestive, nervous, respiratory.
Sum of all cells, tissues, organs and organ systems makes an organism. An organisms is made when a group of organ systems work together.