Who is Teresina Cortez from Tortilla Flat and what is their importance?

Teresina Cortez is a 30-year-old mother of eight, who cannot figure out how she continually gets pregnant. While carrying her ninth child, Teresina depends on her worn-out 50-year-old mother, Angelica, to care for Alfredo, Ernie, Panchito, and five others. Her first three children are all in first grade. They live on beans, that the grandmother cooks and strews on the kitchen floor, but are healthier than any child the school doctor has examined. The beans come from gleaning after the fall threshing. When a drenching rain destroys a whole year's crops, Jesus Maria, who has not visited in months, drops by, rallies the paisanos to provide for the children, and a minor crime wave ensues as the men steal to feed the children. Much of the food that the men shower upon Teresina and her family is spoiled and causes the children bowel troubles. She is ashamed to inform the paisanos but eventually does, so they "liberate" four-hundred pounds of pink beans for her. Teresina proclaims it a miracle and the vieja, who has blasphemed the Virgin for ignoring her prayers, repents. Teresina, who delivers her ninth child, wonders which paisano is responsible for the tenth.