Final answer:
Fiona is likely to experience headaches as a result of her parents' frequent fighting.
Step-by-step explanation:
When people experience stress, their body activates the stress response, which is a complex series of physiological and psychological reactions. One symptom that Fiona is likely to experience as a result of her parents' frequent fighting is headaches. Stress can cause tension headaches or migraines. These headaches can range from mild to severe and can be accompanied by other symptoms like nausea or sensitivity to light and sound.
Learn more about Effects of stress on health