Levels of Organization
The cell is the basic unit of structure and function of a living thing. They all perform jobs inside of us, and are what makes us up. We have many types; skin, brain, ect. There are multi and single celled organisms. Some single cells are volvox, ameobas, ect.
Tissues are made of a group of similar cells that work together to do a specific job in the body.In humans, there are four basic types of tissue: epithelial, connective, muscular, and nervous tissue.
Organs are made up of two or more tissues that work together to do a specific job. Some examples are; heart, kidneys, spleen, ect.
An organ system is a group of organs working together to perform particular jobs. Such as the esophagus, stomach, and intestines working to form the digestive system.
Sum of all cells, tissues, organs and organ systems makes an organism. An organisms is made when a group of organ systems work together. Like how we are made up of organs and cells, other living things are, such as animals.