How did the dred scott decision reverse a previous decision made by congress?

According to the biography of harriet tubman you read, what physical trauma did harriet tubman experience as a young girl? a.) she was repeatedly raped by an overseer.b.)she lost the use of her left leg after it became stuck in a cotton gin.c.)she was beaten within an inch of her life by a slaveholder which caused her to suffer from memory lapses later in life. d.)she was hit in the head with a 2-pound iron weight by an overseer, which caused her to suffer from narcolepsy later in life.