Why does a 5 year old child need more energy than a teenager?

Which of the following is a common response to cell signaling?

The smallest parts of these that retain their original properties are called

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.