O.K is an abbreviation for okay, which is also said as 'oh-kay'
I would love to help answer this but there isn’t enough information to do so!
Think of earth wire as "Earth" which is green in some places. In the same vein, the earth wire is the green one or green with a yellow stripe.
Great question.
Answer:
It is foreshadowing that a stronger man has become king. Duncan was King by God's will.
Explanation: