Read the following passage and answer the questions 10-15.

Unlike the eye, the ear has no lid; therefore, noise penetrates without protection. Loud noises instinctively signal danger to any organism with a hearing mechanism, including human beings. In response, heartbeat and respiration remain accurate. In fact, there is a general increase in functioning brought about by the flow of adrenaline released in response to fear. Because, noise is unavoidable in a complex industrial society. We are constantly responding in the same ways, that we would respond to danger. Recently, researchers have concluded that noise and our response may be so much more than annoyance. It may be a serious threat to physical psychological health and well-being, causing damage not only the ear and brain, but also to the heart and stomach.

What is the author's main point?