Final answer:
The position that eases Mrs. Y's breathing is the upright position.
Step-by-step explanation:
The position in which Mrs. Y's breathing is eased is the upright position. By helping Mrs. Y into a seated position and propping her upright with pillows behind her head and chest, the nurse is facilitating easier breathing. This position allows for better lung expansion and improves the flow of air in and out of the respiratory system.