Final answer:
A gomphosis is a type of fibrous joint, which is functionally classified as a synarthrosis due to its immobility. It connects the teeth firmly within the jawbone. Cartilaginous joints like synchondroses and symphyses offer slight mobility and are classified as amphiarthrosis.
Step-by-step explanation:
A gomphosis is a fibrous joint. More specifically, a gomphosis is a type of fibrous joint where the tooth is anchored to its socket in the jawbone. This type of joint is functionally classified based on the degree of movement it allows. Gomphoses, being fibrous joints, are generally considered immobile (synarthroses), which provide strong, stable connections between bones.
For the other classifications mentioned, synchondroses and symphyses are cartilaginous joints, not synovial. Moreover, the joint between adjacent vertebrae that includes an intervertebral disc is an amphiarthrosis, allowing for slight movement. It is considered a synarthrosis, which means it is immobile and provides a strong connection between adjacent bones. Examples of gomphoses include the teeth anchored in their sockets in the jaw.