D. possess the sphincter of Oddi. Even if you aren't sure of the correct answer, you can see that alternatives A, B, and D all deal with specific facts and details about the lungs. C deals with a main feature of the lungs, respiration. Since C is the more general answer and allows for more variability, it is the correct answer. The correct alternative is often the longest .
Most tests are somewhat consistent about the length of correct answers.
If you notice that most of the correct answers have been the shortest, then when you aren't sure, pick the shortest. If, on the other hand, most of the correct answers have been the longest, pick the longest answer when you are unsure. If you have noticed not particular trend for either the longest or the shortest, try the longest. C. division is indicated D. parentheses preceded by a minus sign may be removed. In this item B is longest and therefore is most likely correct.