Water does not wet an oily glass because

On wearing a rain coat on which some greasy material is coated, a person does not wet in rain because-

If a glass rod is dipped in mercury and withdrawn out, the mercury does not wet the rod because

A mercury drop does not spread on a glass plate because the angle of contact between glass and mercury is

Mercury does not wet glass, wood or iron because

Mercury does not wet the glass. Why?

A mercury drop does not wet glass whereas a water drop sticks to glass. Why?