the iris
The color of your Iris which can be brown black green blue or grey.
drab, gray/grey, iris
The sky doesn't turn grey; there are just grey clouds in the sky that are also blocking the sun.
Get grey hair dye or just let it turn natural grey.
The iris controls the size of the pupil. Which in turn, controls the amount of light entering the eye.
The iris widens to allow as much light ad possible to enter
no
Yes, they may turn grey as you get older.
china
I think, that the loss of blood flow or cut off circulation can cause a foot patch to turn grey.
It would turn gray if it was sick.