Which level of biological organization includes multiple tissues working together to perform broad physiological tasks?

• A. Cells
• B. Organs
• C. Organ Systems
• D. Tissues

Answer: (C)

Organ systems bring together many organs to carry out broad physiological tasks that require coordination across the body. An organ is made of multiple tissue types working together to perform its specific function, but real complexity and integration arise when several organs operate in harmony to achieve wider, system-wide goals like digestion, circulation, or respiration. For example, the digestive system includes the stomach, intestines, liver, and pancreas, each with different tissues, all coordinating to break down food, absorb nutrients, and eliminate waste. This level—organ systems—captures how multiple tissues across different organs work together to manage complex bodily functions.