One of the threadlike processes forming the respiratory surface of a gill.
The correct answer is c
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<span>Joints with no movement are called immoveable or fibrous joints.They are also called synathrosis, they are only separated by a thin layer of fibrous connective tissue e.g are the sutures of the skull.
Joints that are more loosely connected are called freely moveable or synovial joints. They are also called diarthrosis.The joints are held together by an articular capsule comprised of ligaments. A synovial membrane lines the inside of the capsule and secretes synovial fluid which lubricates the joint (hence it's name).</span>
