A group of body structures which perform one or more vital functions for the body is called a:

• A. organelle
• B. tissue
• C. organ system
• D. cell

Answer: (C)

Verified step by step guidance

1. Step 1: Begin by understanding the hierarchy of structural organization in the human body. The levels include: chemical level (atoms and molecules), cellular level (cells), tissue level (groups of similar cells), organ level (structures composed of multiple tissues), organ system level (groups of organs working together), and organism level (the complete human body).
2. Step 2: Define each term provided in the problem: 'organelle' refers to specialized structures within a cell that perform specific functions; 'tissue' is a group of similar cells that work together to perform a specific function; 'cell' is the basic structural and functional unit of life; and 'organ system' is a group of organs that work together to perform one or more vital functions.
3. Step 3: Analyze the question, which asks for the term describing a group of body structures that perform one or more vital functions. This description aligns with the definition of an 'organ system,' as it involves multiple organs working together to sustain life.
4. Step 4: Compare the definitions of the other options ('organelle,' 'tissue,' and 'cell') to ensure they do not fit the description provided in the question. For example, a tissue is a smaller structural unit and does not encompass multiple organs.
5. Step 5: Conclude that the correct answer is 'organ system,' as it matches the description of a group of body structures performing vital functions for the body.