Calcium level in blood is regulated by:

Correct option is C

Correct Answer: (c)
Explanation:
Thyrocalcitonin (calcitonin), secreted by the thyroid gland, lowers blood calcium levels by promoting calcium deposition in bones and reducing calcium reabsorption in kidneys.
Information Booster:
Calcitonin reduces blood Ca²⁺ levels — hypocalcemic hormone.
Parathyroid hormone (PTH) increases blood Ca²⁺ levels — hypercalcemic hormone.
Balance between PTH and calcitonin maintains calcium homeostasis.
Aldosterone controls sodium and potassium, not calcium.
Thyroxine regulates metabolism; somatostatin inhibits hormone release.
Additional Information:
(a) Somatostatin inhibits GH and TSH, not Ca²⁺.
(b) Aldosterone affects Na⁺, K⁺, not Ca²⁺.
(d) Thyroxine controls basal metabolism, not calcium regulation.