Final answer:
Stress responses, such as the fight-or-flight response, helped our ancestors prepare to fight or flee from dangerous situations. However, these responses may have negative health consequences in our modern world.
Step-by-step explanation:
In the story Stress for Success, stress responses helped our ancestors by preparing their bodies to fight or flee from dangerous situations. These responses, commonly known as the fight-or-flight response, included increased heart rate, heightened alertness, and tense muscles. While this response was crucial for survival in the past, it may have negative health consequences in our modern world, such as increased susceptibility to heart disease and impaired immune function.