Juan is the nephew of Aunt Teresa because she is the mother of his cousin Marta, establishing an aunt-nephew relationship. Juan and Marta, being cousins, share a grandparent, making Teresa the aunt of Juan. Regarding the storytelling, Marta is a listener and participant just like her cousins, Juan and Pedro. Her role is to engage and possibly learn from the stories being told by her grandfather, along with improving family bonds through shared history and experiences. 

Grandfather Manuel's stories serve as a bridge between the generations, connecting him to his grandchildren--Juan, Pedro, and Marta--through the shared family lore. This activity underlines the common heritage and reinforces family ties, offering a sense of identity and continuity within the family. It connects the family members by giving the grandchildren a deeper understanding of their family roots, shared through Manuel's personal experiences.
In a family dinner gathering, Grandfather Manuel has his three grandchildren over: Juan, Pedro, and Marta. Juan and Pedro are brothers, while Marta is their cousin. Aunt Teresa is Marta's mother, and she also happens to be Grandfather Manuel's oldest child. During the meal, Grandfather Manuel tells stories from his youth, which he shares with all his grandchildren. Explain the familial relationship between Juan and Teresa. Also, detail the role Marta plays during the storytelling. Finally, describe how Grandfather Manuel's stories connect the family members gathered.

Respond very briefly.