Question

practice it what is the characteristic feature of synovial joints? they have a joint cavity filled with bone. they have a fluid - filled joint cavity. they have a solid joint cavity. they have a gas - filled joint cavity. they have no joint cavity.

Explanation:

Synovial joints are characterized by having a fluid - filled joint cavity called the synovial cavity. This synovial fluid lubricates the joint, reducing friction and allowing for smooth movement.

Answer:

They have a fluid - filled joint cavity.