Simple goiter can be prevented by _________.

Correct Answer: B

Rationale: The correct answer is B: adding iodine to the diet. Iodine deficiency is a common cause of simple goiter. Iodine is essential for the production of thyroid hormones, and a lack of it can lead to the enlargement of the thyroid gland. Adding iodine to the diet helps prevent simple goiter by ensuring the thyroid has enough iodine to function properly. Antibiotics (choice A) are not effective for preventing goiter as it is not caused by bacteria. Surgery (choice C) and hormone therapy (choice D) are typically used to treat goiter once it has developed, not prevent it.

Correct Answer: D

Rationale: The correct answer is D, Both A and C. Melatonin from the pineal gland regulates sleep-wake cycles (A) by influencing the body's internal clock. It also plays a role in sexual development (C) by influencing the release of reproductive hormones. Other choices, B (water balance), are regulated by hormones like ADH and aldosterone, not melatonin. The correct answer encompasses the functions of melatonin in both sleep regulation and sexual development.

Correct Answer: C

Rationale: The correct answer is C: Lacrimal gland. The lacrimal gland is not an endocrine gland because it does not secrete hormones into the bloodstream. It produces tears to lubricate and cleanse the eyes. Adrenal, Pituitary, and Thyroid glands are endocrine glands that secrete hormones directly into the bloodstream to regulate various functions in the body. Adrenal glands produce cortisol and adrenaline, Pituitary gland regulates other endocrine glands, and Thyroid gland produces thyroid hormones. Therefore, Lacrimal gland is the correct answer as it does not secrete hormones into the bloodstream like the other choices.

Correct Answer: D

Rationale: The correct answer is D: Posterior pituitary gland. Antidiuretic hormone (ADH), also known as vasopressin, is produced in the hypothalamus and then transported to the posterior pituitary gland for secretion into the bloodstream. ADH plays a key role in regulating water balance by controlling the reabsorption of water in the kidneys. Choices A, B, and C are incorrect as they are not the primary sites of ADH production and secretion. The adrenal cortex produces hormones like cortisol and aldosterone, the thyroid gland produces hormones like thyroxine, and the pancreas produces insulin and glucagon.

Correct Answer: A

Rationale: The correct answer is A: short chain fatty acids. The colon is where most of the absorption of short chain fatty acids occurs after digestion in the small intestine. Short chain fatty acids are produced by gut bacteria breaking down dietary fiber and play a crucial role in energy production and maintaining gut health. Calcium is primarily absorbed in the small intestine, vitamin K is absorbed in the small intestine and liver, and oligosaccharides are mainly broken down in the small intestine by enzymes. Therefore, A is the correct answer as it aligns with the specific absorption function of the colon.