Final answer:
In 'The Giver', Jonas's sister Lily was received by his parents through an institutional assignment similar to our society's adoption, but in a much more controlled and regulated manner by the society's ruling Elders.
Step-by-step explanation:
In the book The Giver, Jonas's mother and father received his sister Lily through a process established by the community's strictly controlled societal rules. In their society, children are born to Birthmothers and are then assigned to family units at ceremonies. This concept is somewhat similar to adoption in our society, where children are placed with families other than their biological parents.
In the story, parents do not conceive children naturally; instead, children are carefully matched with parents by the Committee of Elders based on certain criteria. This practice contrasts with the typical family structure in our society, where families are often formed biologically or through less regulated adoption processes.