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.
Definition of tread. 1  1a (1) : the part of a wheel or tire that makes contact with a road or rail (2) : the pattern of ridges or grooves made or cut in the face of a tireb : the part of a shoe or boot sole that touches the ground; also : the pattern on the bottom of a sole. 2  2a : the upper horizontal part of a stepb : the width of such a tread.