What is the author's purpose in writing this passage?

Directions: Answer the given question based on the following passage:

Stress has very ancient origin, starting from the pre-historic times. This reference, however, need not be taken to hint that today’s important people have any connection whatsoever to prehistoric men. The very thought is demeaning! The allusion occurs only because the way corporate honchos react to stress is reminiscent of the way Homo sapiens circa 5 mn BC reacted to their stress situations. No connection, whatsoever, just historical reference. So, the pre-historic man, when suddenly faced with, say, a wild bear, experienced a surge of blood pressure, faster heart rate, a tautness of muscles, a rush of adrenaline, release of cortisol in the blood and formation of acid in the stomach to digest food in a jiffy and create glucose and energy. These physiological changes in the body helped the pre-historic fellow out there to respond quickly and strongly to the threat from the grizzly and helped him either flatten the beast’s skull or to sprint away at top speed! As he fought the bear, all these physio-chemical changes and release were used to good effect by the club-wielding caveman, who then, perhaps dragged the bear to his cave and asked his mate to make a teeny-weeny wrap-around skirt for herself from the skin of the animal and a loincloth for him.  
Medically speaking, whenever living beings perceived threat, they quickly released hormones that helped them to survive. These hormones increased heart rate and blood pressure, delivering more oxygen and blood sugar to give more energy and power to important muscles. Acid poured into the stomach to convert any food left there into energy quickly. All these physiological changes helped them to run faster and fight harder. Sweating helped cool the muscles. Blood from surface was moved to the core of their bodies, making the muscles more efficient and reducing blood loss in case of injury. The hormones focussed their attention on the threat, excluding everything else. This response was necessary whenever a living being faced physical threat. Making good use of these physiological changes, human being survived and thrived. He thrived, in fact, so well that he became a threat for the wild animals.
So, when man killed sufficient number of bears and other such dreadful beasts, the animals decided to move away from this ferocious being called man and retired peacefully to forests and jungles where they would only be killed by such animals that would not make loincloths out of them. Man gradually settled in settlements made by him. But his blood longed for the physical challenges of yore. He could not keep without fighting for long, and therefore started fighting his fellows. A long series of battles and wars ensued, ensuring man’s name to be remembered and commemorated in history. These physical challenges were aided and abetted by mental ones where one party had to outmanoeuvre the other through cunning. Victory received the old heady feeling of dragging the beast to the cave for the wrap-around skirt.
Then came the time when fighting physically was considered below dignity in certain human circles.  But human being still liked to fight. The desire for challenge and for winning over difficulties and adversaries is innate to human nature. Slowly, physical battles were becoming history, so, human beings created what they loved. They created someone or something to fight with; they created challenges, when they were already not there. They loved the adrenaline rush. So eventually, commercial, financial, psychological and other such warfare became fashionable among the educated class.