Levels of Organization

Similar cells group together to form a tissue, which performs a specialized function.The tongue, esophagus, stomach and intestine are all organs which form the digestive system.Different kinds of tissues are grouped to form an organ.For example, the stomach is an organ which is made up of many different tissues, such as muscle tissue, nerve tissue and blood tissue.Different organs are grouped into an organ system.The different organ systems form the body and perform processes necessary for life.For example, a bone tissue is made of bone cells.