Question

synarthrotic joints

are immovable joints

characterize all cartilaginous joints

have large joint cavities

are found only in adults

Explanation:

Synarthrotic joints are a type of joint in the body. By definition, synarthrotic joints are immovable. Cartilaginous joints can be amphiarthrotic (slightly movable) in addition to potentially being synarthrotic in some cases (but not all cartilaginous joints are synarthrotic). Synarthrotic joints do not have large joint cavities (that is a feature of diarthrotic joints). Also, synarthrotic joints are not found only in adults (for example, the joints between some bones in a baby's skull are synarthrotic).

Answer:

are immovable joints