X is a drug that contains a mixture of amphetamines. It is used for managing Attention-Deficit/Hyperactivity disorder (ADHD). The drug causes autonomic effects that can be fatal if an overdose is taken. How does X work in the body?

Correct Answer: D

Rationale: The correct answer is D because X, a mixture of amphetamines, works by releasing neuronal noradrenaline, causing excessive sympathetic effects like severe rises in blood pressure. This is how the drug helps manage ADHD symptoms. The other choices are incorrect because A (blocking muscarinic receptors) would not be related to the autonomic effects seen with X, B (blocking β2 receptors) would not explain the fatal autonomic effects, and C (inhibiting MAO) would not lead to the described autonomic effects. Therefore, D is the correct choice based on how X works in the body to produce its effects on the sympathetic nervous system.

Correct Answer: D

Rationale: Certainly! The correct answer is D because it includes statements 3 and 4, which are both true. Statement 3 is correct, as air pollutants can lead to various health issues. Statement 4 is also accurate, as air pollutants can contribute to environmental degradation. Statements 1 and 2 are incorrect as they are not included in the correct answer. Statement 1 may not be universally applicable, and statement 2 does not cover the broad impact of air pollutants on both health and the environment as indicated in statements 3 and 4. Therefore, choice D is the most accurate based on the information provided.

Correct Answer: D

Rationale: The correct answer is D: red supergiant → supernova → black hole. This sequence is part of the life cycle of a very large mass star. Red supergiants are massive stars in the later stages of their evolution. When a red supergiant goes supernova, it explodes in a massive stellar explosion, leaving behind a remnant that can collapse into a black hole due to the immense gravitational forces. Choices A and B are incorrect because planetary nebulae form from the outer layers of lower mass stars, not very large mass stars. Choice C is incorrect as neutron stars are more likely to form from the remnants of less massive stars.

Correct Answer: A

Rationale: The correct answer is A. Eicosanoids are not true hormones because they act locally, not on distal organs like true hormones. Eicosanoids are produced and released in response to specific stimuli at the site of action, affecting nearby cells. This local action distinguishes them from true hormones, which are produced in one part of the body and travel through the bloodstream to distant target organs to elicit a response. Choices B, C, and D are incorrect because eicosanoids do have target organs (B), mediate inflammatory reactions (C), and are lipid in nature (D), but these characteristics do not define them as hormones.

Correct Answer: D

Rationale: The correct answer is D: cholecalciferol. The skin produces cholecalciferol, also known as vitamin D, in response to sunlight exposure. This hormone plays a crucial role in calcium absorption and bone health. Erythropoietin (A) is produced by the kidneys to stimulate red blood cell production. Melatonin (B) is produced by the pineal gland to regulate sleep-wake cycles. Renin (C) is produced by the kidneys to regulate blood pressure. Therefore, the skin does not produce erythropoietin, melatonin, or renin, making them incorrect choices.