TOEFL Reading: ETS-TOEFL阅读机经 - E71C54HI5EYB231DL$

According to paragraph 5, which of the following is true about the vertical tunnels constructed by dry-diet termites A. They allow water from the surface to accumulate underground. B. They are generally wider at the top than at the bottom. C. They provide extra space so that dry-diet termite populations can expand. D. They are constructed to provide direct access to water.