Parathyroid hormone is directly involved in the bones, kidneys, and the small intestine. In the bones, PTH stimulates the release of calcium in an indirect process through osteoclasts which ultimately lead to resorption of the bones.
2n because when 2 gametes of n amount of DNA fertilise together they make an organism that is similar to its parents and have the total amount of DNA as 2n, just like parents.
