Which hormone is responsible for regulating water reabsorption in the kidneys?

A. Humerus: The humerus is the long bone of the upper arm, connecting the shoulder to the elbow. It is not associated with the term “collarbone.”

B. Scapula: The scapula, or shoulder blade, is a flat triangular bone located on the posterior side of the ribcage. It does not serve as the collarbone.

C. Clavicle: The clavicle is commonly known as the collarbone. It is a long, slender bone that connects the sternum to the scapula, providing support and stability to the shoulder and allowing a wide range of arm movement.

D. Sternum: The sternum, or breastbone, is a flat bone located in the center of the chest. It articulates with the clavicles but is not referred to as the collarbone.

A. Adrenal cortex: The adrenal cortex secretes aldosterone, a hormone that regulates sodium and potassium levels by increasing sodium reabsorption and potassium excretion in the kidneys. This helps maintain blood pressure, fluid balance, and electrolyte homeostasis.

B. Pancreas: The pancreas produces insulin and glucagon to regulate blood glucose levels. It does not have a direct role in sodium or potassium balance.

C. Pineal gland: The pineal gland secretes melatonin, which regulates circadian rhythms and sleep-wake cycles. It is not involved in electrolyte regulation.

D. Thyroid gland: The thyroid gland produces thyroid hormones that regulate metabolism, growth, and development. It does not directly control sodium or potassium homeostasis in the body.