Final answer:
Frederick Douglass described the forced separation of enslaved children from their parents as a cruel practice in the slave system.
Step-by-step explanation:
Frederick Douglass described the practice of forced separation of enslaved children from their parents as 'a marked feature of the cruelty and barbarity of the slave system.' In his narrative, Douglass recounted how enslavers would sell their own children born with enslaved women to please their White wives. This characteristic practice of slavery is emphasized in the first paragraph of the selection from Frederick Douglass.