Final answer:
The author included the "Osiris and Set" section to explain how the Osiris myth influenced Ancient Egyptian beliefs about the afterlife, justified the royal succession, and reflected natural phenomena like the Nile's flooding through the concepts of death and rebirth.
Step-by-step explanation:
The author's purpose for including the section "Osiris and Set" in the Newsela article "How Ancient Egyptians Shaped the World's View of Life After Death" is to illustrate the significance of the Osiris myth and its profound impact on Ancient Egyptian beliefs regarding the afterlife.
Through the narrative of Osiris, the god of the underworld, who was killed and later resurrected, Ancient Egyptians interpreted the cycles of the Nile and saw a representation of rebirth and the possibility of life after death, thus influencing their burial practices and religious rituals.
The storyline also provides a theological underpinning for the succession of kings, associating them with Horus, who avenges his father Osiris, thus securing their divine right to rule and their eventual union with the divine in the afterlife.