Calcium is to bones as ______ is to blood.
Assertion(A): Excess amount of calcium is regulated by calcitonin. Reason(R): Calcitonin deposits excess calcium in the blood in bones.
Blood calcium level is a result of how much dietary calcium is absorbed and how mich is lost in urine, how much bone dissolves releasing calcium into the blood and how much calcium from blood enters tissues. A number of factors play an important role in these processes. Mark the one which has NO role