Cells specialize to form tissues that group together to perform shared functions. Tissues then combine to form organs which work together in organ systems to carry out body functions. For example, the stomach organ contains muscle tissue made up of individual muscle cells, and is part of the digestive system organ system.

1. -LEVELS OF ORGANISATION-SPECIALIZATION OF CELLS

2. LEVELS OF ORGANISATIONOrganelle: a structurewithin a cell.Tissue: a group of cellswith similar structures,workingtogethertoperform a sharedfunction.Organ: a structuremade up of a group of tissues, workingtogethertoperformspecificfunctions.Organsystem: a group of organswithrelatedfunctions, workingtogethertoperformbodyfunctions.

3. Specialization of cells

6. Howcellsformtissues

8. Organs, cells and tissuesThe stomach is an organ,part of the digestive systemThe stomach wall contains muscle tissueThe muscle tissue consists of muscle cells

9. Systems