a
really really really realy bad fungus...or frostbite
Rusting
Mold
because it is li8mp and lifeless..
Gravitation.
Poor circulation. You should see a doctor immediately!
Brake dust!
Bugs are wiping their asses on them
Tulsi leaves turn black due to oxidation, which occurs when the leaves are exposed to air for a prolonged period of time. This process causes the leaves to lose their green color and turn black.
black because they get dirty and holes because they get worn out
It depends on how old you are and what your life expectancy is. Human eyes will not turn black during a person's life.
Too much iron in the water
Alkaptonuria is an inherited condition that causes urine to turn black when exposed to air.