Why do scientist try to repeat other scientists experiments

Name one similarity and one difference between the morphology of a brachiopod and a bivalve

The transport tubes for food coming down the plants 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.