a circle can do neither, if you mean a sphere then I must inform you to remember that a circle is 2D and a sphere is 3D..... So spheres can't do either, they often get tired and goto sleep.
Because the sides are like a circle.
no
Slide.
Circle Slide was created in 1990.
Yes
cylinders: slide on the small sides, roll on the round one
You slide,roll,and tumble
a ball
Yes
both
yes. it can slide if on a slippery surface facing downwards
A cylinder