The primary contributor of skin color is the pigment known as melanin. The quantity of melanin in the skin varies based on genetic factors and is also dependent on the degree of sun exposure. Melanin is produced by specialized pigment cells known as melanocytes.
Average new tires used on cars typically start with 10/32 to 11/32 of original tread depth. Tires are considered worn out. In most States when they reach 2/32 of remaining tread depth. Ans 2 - Here in Canada (and I'm sure in many parts of the US ) we get a lot of rain.
NASCAR tires do not have tread because the cars do not drive on a wet surface. Tread helps channel water away from the surface of the point where the rubber meets the road. Siâ¦nce NASCAR does not race in the rain, a smooth tire gives more surface for the tire for the most traction and speed. 4 people found this useful.