Answer:
Synovial Fluid is the correct answer.
Step-by-step explanation:
Synovial joints are joints that can move in many directions. Hips, shoulders, elbow, knees, wrists and ankles have synovial joints, they are filled with synovial fluid, it is a lubricants for the joints so that they can move easily but it doesn't strengthens or stabilises the joint. There are six types of this joints pivot , hinge, plane, saddle, ball and socket and condyloid.