Shortly before the election for governor, two polls of likely voters are released. The first poll, based on a survey of 1,000 voters in rural areas, predicts a victory for candidate A. The second poll, based on a survey of 400 voters in a large city, predicts a solid victory for candidate B.

Which of the following best describes the purpose of the parathyroid hormone? a. it decreases the blood calcium level and decreases blood phosphorus level. b. it decreases the blood calcium level and increases the blood phosphorus level. c. it increases the blood calcium level and increases blood phosphorus level. d. it increases the blood calcium level and decreases blood phosphorus level.