The answer is:
It suggests that Ben's father's intellectual curiosity is a positive trait.
According to the passage, Ben's father inquisitiveness and intense desire for knowledge equals U.S. president's Abraham Lincoln's curiosity. As a result, he takes his family on holiday from Michigan to South Dakota in a comfortable trailer to go camping and see waterfalls, forests and Mount Rushmore.
Answer: each of which consists of an unstressed syllable followed by a stressed syllable
