The joints in the fingers are
a. pivot joints
b. saddle joints
c. condyloid joints
d. ball-and-socket joints

The joints in the fingers are one of the examples of condyloid joints. The condyloid joint is formed when a bone with an elliptical end is connected to another bone with an elliptical cup. It allows for rotation in two planes. It is similar to ball and socket, but doesn't allow for full 360 degree rotation.

The speed of  sound:   sound travels  at different speeds depending on what it istraveling through. of the three mediums (gas, liquid, and solid)  sound waves travel the slowest through  gases, faster  through  liquids, and fastest  through  solids.