TOEFL Listening: TPO-TOEFL阅读TPO - IE3J74Y41H44918CN$

Paragraph 4 implies which of the following about the roots of plants? A. They prevent water from reaching the vadose zone. B. They mark the boundary between the vadose zone and the water table C. They do not typically get their water from the water table. D. They help keep the water table from dropping farther.