Question

what did the dialysis lab demonstrate about the walls of the small intestine?
there are gaps or holes that large and small molecules can leave through.
the small intestine doesnt let any molecules through its walls.
there are gaps or holes that small molecules can leave through.

Explanation:

The small intestine's walls have gaps or holes (pores) that allow small molecules (like nutrients) to pass through via processes like diffusion and osmosis. Large molecules (e.g., proteins in their native form) generally cannot pass through these gaps. The dialysis lab, which mimics some aspects of semi - permeable membrane function (similar to the small intestine's wall in some ways), would show that small molecules can traverse.

Answer:

There are gaps or holes that small molecules can leave through.