Which of the following statements is (are) true concerning calcium? a. Calcium is an electrolyte whose balance in the blood is maintained by the skeletal system through deposition and reabsorption. ...

Which of the following statements is (are) true concerning calcium?

a. Calcium is an electrolyte whose balance in the blood is maintained by the skeletal system through deposition and reabsorption.

b. Calcium is reabsorbed by the production of an acid by osteoclasts.

c. Calcium is found in trabeculae.

d. Calcium is deposited in bone through a positive-feedback mechanism of mineral crystal deposition.

e. PTH causes calcium to be absorbed by the small intestines if there is calcitriol.