All the bones listed below belong to the axial skeleton, except one, which belongs to the appendicular skeleton.

Choice A reason: The humerus is the upper arm bone and articulates with the glenoid cavity of the scapula, not the acetabulum.

Choice B reason: The patella is the kneecap and articulates with the femur, not the acetabulum.

Choice C reason: The acetabulum is the deep socket in the pelvic bone that articulates with the head of the femur, forming the hip joint. This ball-and-socket configuration allows for a wide range of motion and stability.

Choice D reason: The tibia is the larger bone of the lower leg and articulates with the femur at the knee joint and the talus at the ankle. It does not connect to the acetabulum.

Choice A reason: Symphyses are cartilaginous joints where bones are joined by fibrocartilage. They allow limited movement, such as in the pubic symphysis, but are not the most movable joints.

Choice B reason: Synovial joints are the most movable type of joints in the human body. They feature a joint cavity filled with synovial fluid, articular cartilage, and a fibrous capsule, allowing for a wide range of motion. Examples include the shoulder, hip, and knee joints.

Choice C reason: Syndesmoses are fibrous joints where bones are connected by ligaments or interosseous membranes. They allow more movement than sutures but are still relatively limited compared to synovial joints.

Choice D reason: Gomphoses are immovable joints found between teeth and their sockets. These joints are highly stable but do not permit movement.