Which joint type is primarily held together by fibrous tissue and typically has no movement?

The correct choice is synarthroses, as this joint type is primarily characterized by its immobility. Synarthroses are joints that are connected by dense connective tissue, which includes fibrous tissue, providing structural integrity and stability without allowing for movement. This type of joint is essential for protecting internal structures and maintaining body integrity, as seen in the sutures of the skull.

Other joint types, such as diarthroses, allow for free movement and are typically synovial joints, while amphiarthroses permit limited movement and are often connected by cartilage or ligaments. Cartilaginous joints also allow for some movement but not as freely as diarthroses. Understanding the distinctions between these joint types helps clarify the classification of joints based on their structure and the degree of movement allowed.