Final answer:
The principle or policy is reasonable efforts, which requires a child welfare professional to prevent the removal of a child from the home.
Step-by-step explanation:
The principle or policy that requires a child welfare professional to exercise all reasonable actions to prevent the removal of a child from the home is reasonable efforts. Before a child is removed from the home, efforts must be made to address the safety issues and support the family in order to keep the child at home whenever possible.