Frederick Douglass displayed a powerful capacity to stir both readers of his printed work and audiences in lecture halls in the service of what reformist cause?

a movement to abolish the enslavement of African Americans

Explanation:

In the 17th and 18th century, several people were kidnapped from Africa, and they were taken to the American colonies and forced to become slaves. These people worked as servants and were involved in crops production for the whites. However, Frederick Douglass displayed a powerful capacity to stir both readers of his printed work and audiences in lecture halls in the service of a movement to abolish the enslavement of African Americans.