So that when you run on it you don't slip, and can change direction easily.
if it is rough it will bounce lower and it is smooth it will bounce higher
True, but only to a point. If the surface is too rough debris can get lodged between the wheels causing them to lock up. Which generally will lead to your face meeting the previously mentioned rough surface. However if the surface is not rough enough then it is difficult for the wheels to get a grip on the surface. Which usually will also lead to a meeting between the very smooth surface and your face.
The rough endoplasmic reticulum has ribosomes on its surface. This is what make is "rough"
Smooth surface
The rough surface is better than the smooth surface for the frictional force to act.
A rough and unpolished surface is called "unrefined" or "coarse."
The Rough Endoplasmic Reticulum (Rough ER) has ribosomes on its surface.
Sanding the surface with sandpaper or using a sander can help smooth out a rough surface by removing imperfections and creating a more even texture. Applying a coat of primer or filler before painting or finishing can also help to create a smoother surface.
A basketball will roll faster on a smooth surface due to less friction compared to a rough surface. The rough surface creates more resistance, slowing down the ball's movement.
when light hits a rough surface it scattters.
The moon's surface is rough - due to numerous impacts from meteorites
The endoplasmic reticulum has ribosomes attached to its surface, making it the rough endoplasmic reticulum (RER). These ribosomes are responsible for protein synthesis.