Final answer:
Anne is advised to thank God for her blessings and to ask for what she wants, reflecting themes of gratitude and piety.
Step-by-step explanation:
Marilla suggests that Anne should give thanks to God for her blessings and to ask God for what she desires. In the context of literature, this advice embodies themes of gratitude and piety, which are common in moral and didactic narratives. Encouraging Anne to be thankful reflects a character's worldview focused on humility and recognizing the good already present in one's life, while also maintaining hope and faith by making petitions for her needs and wants.