It is rate for any motion to a. stay the same for very long
b. change quickly
c. increase in velocity
d. decrease in speed

a. stay the same for very long

Explanation:

It is rare for any motion to stay the same for a very long time. The force applied on a body causes changes in the magnitude of motion.

the answer is b, have negligible mass

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.