Answer:
1. The black people made actions.
- Famous abolitionist : Olaudah Equiano
2. The white people's attitudes changed.
- The Christians called Quakers were against slavery. They thought it was completely against the Christian's studies.
3. Because of economic problems.
- The plantation owners recognized that employing workers and paying them will be efficient for them to earn money. (Unpaid slaves worked slowly and broke the equipments so it was a big loose for the owners.)