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.
1 Tire tread is composed of several ribs. 2  Turn the penny so that Lincolnâs head points down into the tread.  See if the top of his head disappears between the ribs. If it does, your tread is still above 2/32â , If you can see his entire head, it may be time to replace the tire because your tread is no longer deep enough.