The human digestive system is composed of many parts. Each one has a specific function. For example, teeth crush food into small pieces that can be swallowed. Muscle tissue contracts to push the food through the system. The pancreas produces enzymes that chemically break the food down. Cells inside the small intestine pass nutrients into the bloodstream. The large intestine stores and removes waste.
The organs, tissues, and cells of the digestive system have a wide variety of structures and jobs.
Why are organs, tissues, and cells all classified as one system?
A
They all work together to process food into nutrients and waste.
B
They are all connected by networks of neurons and blood vessels.
C
At the cellular level, they all take in nutrients to use for supplies and fuel.
D
Together, they form a continuous path that moves food through the body.
A
They all work together to process food into nutrients and waste.