TOEFL Listening: ETS-TOEFL听力机经 - 1P9X6VC5AZC4RUXQP$

According to the professor, what determines the temperature of the barriers in the facility's basements? A. The amount of heat generated by the facility's solar panels B. The amount of heat transferred from the facility's windows C. The temperature of air drawn in from other locations D. The temperature of the surrounding soil