Which key feature distinguishes a synovial joint from other joint types?

the tree main features of a synovial joint are articular capsule, articular cartilage and synovial fluid.

Explanation:

I just learned this but I’m pretty sure average is the same speed over time and relative is the speed so let’s say a car was driving down the freeway and they we’re driving at the same speed that would be average speed and say a car was driving down a street with different speeds that would be relative speed