Final answer:
The sternum is not part of the appendicular skeletal system, while the femur is part of it.
Step-by-step explanation:
The appendicular skeletal system is made up of the bones and structures that make up the limbs and girdles. The sternum, also known as the breastbone, is part of the axial skeletal system, which includes the bones of the skull, spine, and thorax, and is not part of the appendicular skeletal system.
On the other hand, the femur is one of the long bones in the body and is part of the appendicular skeletal system. The femur is the bone located in the thigh and forms the connection between the hip and knee joints.
Therefore, the correct answer is sternum.
Learn more about Appendicular skeletal system