What part of the appendicular skeleton is responsible for attaching the arms to the axial skeleton?

The pectoral girdle is the correct part of the appendicular skeleton that is responsible for attaching the arms to the axial skeleton. This girdle consists of the clavicles (collarbones) and the scapulae (shoulder blades). It provides structural support and stability for the upper limbs while allowing a wide range of motion for the arms. Unlike the pelvic girdle, which connects the legs to the axial skeleton, the pectoral girdle specifically serves to connect the arms and provide attachments for muscles that enable movement.

The vertebral column, while significant in supporting the body and protecting the spinal cord, does not directly attach the arms. Similarly, the axial skeleton encompasses the skull, vertebral column, and rib cage but is a broader term that includes the central core of the body and does not specify the attachment of the arms. Hence, the pectoral girdle's role in facilitating arm mobility and connection to the body is what makes it the correct answer.