Why is hair strands do not decompose?

human hair strands particularly on the head

Why is hair strands do not decompose?

First of all you are not correct, hair strands do in fact decompose. But becuase the protein composition of hair is far more resistant to ourside forces than skin, and thus lasts considerably longer.

Why is hair strands do not decompose?

Human hair does decompose, just very slowly. If it is still attached to your head and you are alive, and wash your hair regularly, it will last a long long time. If you cut your hair off and bury it in the ground, chemistry and microorganisms will slowly decompose the hair.