The bones of the upper extremities include the:

The correct response indicates the bones involved in the structure of the upper extremities. The humerus, located in the upper arm, connects the shoulder to the elbow, while the radius and ulna are the two bones in the forearm that extend from the elbow to the wrist. The combination of the humerus and radius accurately represents two of the major bones in the upper extremity anatomy, thus supporting the correct choice.

The other options include bones that aren't part of the upper extremities. For example, the femur is part of the thigh and relates to the lower extremities. The tibia and fibula are also located in the lower leg and do not pertain to upper limb anatomy. Therefore, the proper identification of humerus and radius in the correct answer underscores the foundational knowledge of human anatomy relevant to outdoor emergency care and the focus on the upper body’s skeletal structure.