Answer:
Cell----- Tissue----- Organ---- Organ system
Step-by-step explanation:
All living organisms are made up of cells. However, multicellular organisms contains many different kinds of cell, which are required to perform certain roles that will be of utmost benefit to the organism as a whole. The level of organization of life follows an hierarchical classification.
As earlier stated, CELLS are the simplest unit of every living organism. Cells that come together to function in a similar role are called TISSUES. Tissues that work together collectively form an ORGAN. Organs that perform similar functions to achieve a similar goal are called the ORGAN SYSTEM. The different systems in a multicellular organism makes up the whole ORGANISM.
Hence, Cell----- Tissue----- Organ---- Organ system is the organized level of organization from the smallest (cell) to the largest (organ systems).