The heart is located ________ the sternum?

The heart is located behind the sternum, which is the breastbone that serves as a central part of the ribcage. The anatomical position of the heart is such that it is not directly visible from the front of the body, as it resides in the thoracic cavity, shielded by the sternum and the ribs.

The other options do not accurately describe the heart's relationship to the sternum. The heart is situated more towards the center and left side of the thorax, but it is primarily protected by the sternum rather than positioned to the right or left side of it. Therefore, "behind the sternum" perfectly describes its anatomical position, providing the necessary protection from external impacts.