Using a microscope at low magnification, you study the lining of the small intestine of an anesthetized rat. you would see which is responsible for the movement of food molecules from the gut into the rat's body. as you zoom in to observe this structure at much higher magnification, you would see which is responsible for movement of molecules between fluid compartments.

Using a microscope at low magnification, you study the lining of the small intestine of an anesthetized rat. You would see epithelial tissue, which is responsible for the movement of food molecules from the gut into the rat's body. As you zoom in to observe this structure at much higher magnification, you would see a cell membrane, which is responsible for movement of molecules between fluid compartments

Explanation:

The epithelial tissue and the movements from muscular contractions called "peristalsis" let the food molecules move in the gut.

Cell membranes are dynamic structures that are able to transporte different molecules like lipids, proteins, metabolites.