What the blanks mean

How can an organ, such as the lungs, work for multiple body systems?

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.

When mitochondrial dna from living relatives was compared with mitochondrial dna from the skeletons, scientisits determined that skeletons 3,4,5,6 and 7 were members of the romanov family. which of these skeletons can be identified by name based on the evidence you have? explain your answer.