Answer:
Step-by-step explanation:
The quote that explains why Athena's advice changes the way Telemachus acts, speaks, and carries himself is:
"I know you have spoken out of a wise and friendly heart."
This quote indicates that Telemachus recognizes the wisdom and sincerity behind Athena's advice. He acknowledges that her words come from a place of genuine care and guidance. This understanding and trust in Athena's intentions influence his behavior, speech, and demeanor as he accepts and internalizes her counsel.