Where the characters and setting believable and effective?

I think the question wants you to be more specific about how the setting and characters translate into believable fiction. Julia Alvarez tries to give us a realistic account of the Mirabal sisters and their families in the Dominican Republic under the Trujillo regime. She tries to give us the feelings go the culture, oppression and beauty of the place and people. Each of the sisters have strong personalities, we really get to meet them up close. Through the eyes of Dede, the only surviving sister, we can almost feel the sweet scent of the Dominican air in the morning, the oppressive Trujillo's constant torment or the stifling prisons that many of the characters end up in. The reader knows this is a different place with different rules.