Final answer:
d) Body. The longest part of the sternum is the Body.
Step-by-step explanation:
The longest part of the sternum is the Body.
The sternum, also known as the breastbone, consists of three parts: the manubrium, body, and xiphoid process. The body of the sternum is the elongated, central portion. It measures approximately 4 inches in length, making it the longest part of the sternum.
For identification purposes, the manubrium and body join together at the sternal angle. The sternal angle is a slight bend where the two components meet. The second rib attaches to the sternum at this angle, making it an important landmark.