Final answer:
Mercy Otis Warren participated in colonial politics during the 1760s and 1770s by opposing British reform measures, publishing anti-British works, and writing a three-volume history of the Revolution.
Step-by-step explanation:
Mercy Otis Warren, a prominent figure during the revolutionary era, participated in colonial politics during the 1760s and 1770s by actively opposing British reform measures and publishing anti-British works. She challenged gender assumptions and traditions by stepping out of the female sphere and into the male-dominated sphere of public life. In the late 1770s, Warren started a project to write a three-volume history of the Revolution, which she eventually published in 1812.