The entire body of a black sheep is covered in wool, just like any other sheep. The wool can vary in color, with black sheep producing black wool.
Wool
White since the wool tends to be higher quality than the wool from a black sheep. Also white wool can be dyed a multitude of colours.
The skin
No. Not even black sheep.
Harvest wool
You can dye wool or sheep black with it.
yes
The possessive form of "wool of the sheep" is "the sheep's wool".
Most sheep are white, but there are other colors. The second most common color is black. And white ones can have white OR black faces.
The popular nursery rhyme "Baa, Baa, Black Sheep" mentions the black sheep having three bags of wool - one for the master, one for the dame, and one for the little boy who lives down the lane.
The master.