4 adjectives to describe keynotes

The opening colloquy of the Witches in Macbeth, strikes the eerie keynote, but does nothing more.

Peaceful villages as sleepy as any in our own country districts appeared at frequent intervals, and easy prosperity was the obvious keynote of the well-wooded and undulating countryside.

Nevertheless, as far as the doctrine of servicethe serving of a cause higher than one's own self, even at the sacrifice of one's individuality; I say the doctrine of service, which is the greatest that Christ preached and is the sacred keynote of his missionas far as that is concerned, Bushido is based on eternal truth.

In all of these the administration of the respective internal secretions increases the burning up of material in the body, and all of them have a higher rate of tissue combustion than their confreres, with a subthyroid or subpituitary keynote in their cell chemistry, or with insufficient interstitial cell action.

4 adjectives to describe  keynotes