How is the woman's daughter an integral part of the plot in the story, The Woman at the Store?

The woman’s daughter is an important side character in this story. The various ways in which she interacts with the other characters demonstrates important aspects of those characters’ personalities. For example, her interactions with Jim on page 64 and 65 reveal that Jim is rude and takes pleasure in bullying children. Furthermore, this character is important because she is responsible for the major plot point at the end of the story, in which the reader learns that the woman killed her husband.