Answer:
B.the speed at which the disturbance propagates
a great example would be sound. In air, the speed of sound is about 343m/s, but in iron, the speed of sound is about 5120 m/s that's about 15 times faster than air. Why is this? Well, it is because in the air the molecules are very spread out and have a long way to travel before they can bump their neighbors. But in iron, the molecules are much much closer and have a shorter distence before they hit their neighbors.
the mean of the data set is 6ml
I would say D would be the answer. but is this even a real like homework question
The sphere slow down due to friction force between the surface of the sphere and the surface on that the sphere is rolling . The friction force acting against the motion of the sphere. Thats why it is slowed down. In fact not only a sphere, anything can not slow down untill a force act against it's motion.