Please help answering this guys. you will score 30 points, I need it right now . its biology.

Cartilage is needed for support between joints. Because it is not as rigid as bone, it allows some flexibility but has more structural integrity than muscle. Synovial fluid is important to joints lubricated and moving smoothly, just like oil in a machine. The machine needs the oil to continue functioning at the best of it's ability.

... I think it's Autotrophs..

if it's wrong I'm sorry :/ ..