Complete the Sentence with the Best Term

Complete the sentence with the best term.
Dropdown Options:
Build new bone
Calcitriol
Cyclic AMP
Decrease absorption of calcium
Decrease reabsorption of calcium
GI tract and osteoclasts
Increase absorption of calcium
Increase reabsorption of calcium
Kidney cells
Osteoclasts
Osteoclasts and kidney cells
Parathyroid hormone
PT gland cells
Release calcium to enter blood
[dropdown 1] the receptors,respond to low blood calcium levels.
[dropdown 2] input activates the control center when blood calcium is low.
[dropdown 3] is/are the effector(s)of PTH.
Osteoclasts [dropdown 4] in response to PTH:
The kidney [dropdown 5] in response to PTH:
[dropdown 6] is secreted in response to PTHs effects on the kidney.