Read the passage carefully and answer the following question. One theory of accidents is what experts call the Swiss Cheese model. A slab of Swiss cheese hasseveral holes, randomly and unevenly distributed over its surface. If several slabs are stackedtogether, it would be impossible for something to slip through unless all the holes happen to lineup. If even one slab doesn’t align, the impending catastrophe will meet a layer of resistance, and theworst is averted. Aviation professionals will tell you that plane crashes never happen for a singlereason. There may be an identifiable primary factor, but it’s usually a chain of events, an array of circumstances neatly piling up. Which of the following statements can be BEST concluded from the passage?