Answer:
1. These battles marked the official start of the American Revolution
2. The Colonists had knowledge of the land, and were able to get to higher ground.
Step-by-step explanation:
The battles of Lexington and Concord were the first engagements between military elements of the British and the Colonists when the British tried to destroy colonial military supplies and arrest some colonist leaders. Colonist militia got wind of this and engaged the British in what would become the first battle in the war.
The Colonists fighting at Bunker Hill knew the American terrain better than the British because they grew up on this land. They were therefore able to get to higher ground from whence they terrorised the British and inflicted heavy casualties.