Final answer:
On an abdominal x-ray of the large bowel, the haustra are the prominently visualized features, which are small pouches formed due to the contractions of the teniae coli.
Step-by-step explanation:
On an abdominal x-ray of the large bowel, the feature that is prominently visualized is the haustra. Haustra are the small pouches formed along the large intestine due to tonic contractions of the teniae coli, which are three bands of smooth muscle. These give the colon its wrinkled appearance. While plicae circulares and valvulae conniventes are features found in the small intestine, and teniae coli are the smooth muscle bands responsible for creating haustra, it is the haustra themselves that are visible on an x-ray as they create the segmented appearance of the colon.