Question

Even though the bones are very hard, the two bones that form a joint do not cause friction, except in the elderly. Which of the statements below is an appropriate justification for the smooth movements of these bones? A. Synovial fluid, which is present in the space between the joints, acts as a lubricant, thus avoiding friction of the two bones forming a joint. B. Cartilaginous disc, which is present in the space between the joints, acts as a lubricant, thus avoiding friction of the two bones forming a joint. C. Acetylcholine, which is present in the space between the joints, acts as a lubricant, thus avoiding friction.

Answer 1

A. Synovial fluid, which is present in the space between the joints, acts as a lubricant, thus avoiding friction of the two bones forming a joint.
it is the main thing that makes fiction lesser.

Answer 2

I think the correct answer from the choices listed above is option A.  The smooth movements of the bones are cause by the synovial fluid which  is present in the space between the joints, acts as a lubricant, thus avoiding friction of the two bones forming a joint. Hope this answers the question.