clay, grass, and sand
Ring
There are three surfaces are used in field hockey: 1. Mud surface. 2. Grassy groun. 3. Afterterf (santhetic)
By smoothing the surfaces, lubricating the surfaces, inserting ball bearing or their equivalents between the surfaces.
Yes, anything from 2 surfaces creates friction.
A cylinder
A polyhedron.
A cylinder has three faces and two round surfaces.
Box graters have four different cutting surfaces. Three grating surfaces and one slicing surface are standard.
A wedge from a spheroid is one example.
Three: top, bottom, and middle
triangular pyramid
Frogs uses respiratory surfaces which totals to three to exchange gases on its surroundings. The three respiratory surfaces are the skin, its lungs, and the lining of their mouth.