K^+ is actively reabsorbed from the GIT lumen in the:

Correct Answer: D

Rationale: K^+ is actively reabsorbed in the distal colon; most GIT segments secrete K^+ into the lumen.

Correct Answer: B

Rationale: Cortisol is the corticoid that counteracts the inflammatory process. Thyroxine is secreted by the thyroid gland. Insulin is secreted by the beta cells of the pancreas. It is responsible for regulation of blood glucose levels. Norepinephrine is secreted by the adrenal medulla in response to stimulation from the sympathetic nervous system. It functions as a pressor (causing blood vessel constriction) hormone to maintain blood pressure.

Correct Answer: C

Rationale: Hormones are typically secreted into the bloodstream by endocrine glands and travel through it to reach their target tissues, making the bloodstream the primary mode of transport.

Correct Answer: B

Rationale: The Assertion (A) is TRUE because the hypothalamus produces releasing hormones to regulate anterior pituitary hormone secretion. The Reason (R) is TRUE as thyroxine helps regulate body temperature and is secreted by the thyroid near the larynx. However, R does not explain A, as they address different mechanisms.

Correct Answer: D

Rationale: Adrenaline, secreted by the adrenal medulla, prepares the body for fight-or-flight responses when triggered by the sympathetic nervous system.