Correct Answer: C

Rationale: In negative feedback mechanisms, changes away from the normal state stimulate changes in the opposite direction. This is a fundamental concept in biological systems where the response to a stimulus opposes the initial change, helping to maintain homeostasis. Choice A is incorrect because negative feedback does not stimulate changes in the same direction. Choice B is incorrect because negative feedback does not inhibit all body reactions, but rather specific responses. Choice D is incorrect because negative feedback does not stimulate a reduction in all body requirements, but rather adjusts specific functions to restore balance.

Correct Answer: D

Rationale: Magnetic resonance imaging (MRI) uses high-frequency sound waves to create detailed images of the inside of the body. X-rays (Choice A) use electromagnetic radiation, not sound waves, making it an incorrect choice. A radio antenna (Choice B) is used for communication, not for MRI imaging. Radioisotopes (Choice C) are used in nuclear medicine imaging techniques, not in MRI scans. Therefore, the correct answer is high-frequency sound waves (Choice D) as they are utilized in MRI technology to produce images.

Correct Answer: B

Rationale: The statement that the parietal pleura is a visceral membrane is false. The parietal pleura is actually a membrane that lines the thoracic cavity and is responsible for protecting and cushioning the lungs. Visceral pleura, on the other hand, is the membrane that covers the surface of the lungs. Therefore, the parietal pleura is not a visceral membrane, making the correct answer 'False.' Choices C and D are not relevant as the question is asking for a true/false statement.

Correct Answer: A

Rationale: The statement provided in the question is true. Ceroid pigments and lipofuscin are products of cellular damage and aging. These substances accumulate within cells over time and can impair cellular functions, including the ability to withstand the damaging effects of oxygen free radicals. Choice B, 'False,' is incorrect because the accumulation of ceroid pigments and lipofuscin does indeed impair a cell's ability to deal with oxidative stress. Choices C and D are also incorrect as the statement is true.

Correct Answer: A

Rationale: The parietal pericardium is a tough, fibrous outer layer that is attached to the diaphragm and the sternum but not directly to the surface of the heart. It forms a sac around the heart known as the pericardial sac. Therefore, the statement that the parietal pericardium is attached to the surface of the heart is false.