Assertion: Maximum degree of mobility can be seen with a ball and socket synovial joint.

Reason: A ball can rotate in a hollow spherical socket on infinite axises.

Ball and socket joints are considered to have maximum mobility because they allow movement in multiple directions. These joints are formed where a spherical bone head fits into a cup-like cavity of another bone. This structure enables movement in all three planes of motion, which are flexion/extension, abduction/adduction, and rotation.