Final answer:
The spine and hips are classified as irregular bones due to their complex shapes and unique functions in the human body.
Step-by-step explanation:
The spine and hips are classified as irregular bones in the human skeleton. Irregular bones have complex shapes with short, flat, notched, or ridged surfaces. For example, the vertebrae make up the spine, and these bones have a complex structure that allows them to protect the spinal cord and provide flexibility and stability to the spine. Similarly, the hip bones have a unique shape tailored to support the body's weight and enable a range of movement. Both the vertebrae and the hip bones are not long, flat, or any of the other types of bones, making them fit into the category of irregular bones.