Which of the following statements about the autonomic nervous system (ANS) is true?

Correct Answer: D

Rationale: The correct answer is D because the autonomic nervous system (ANS) is responsible for controlling involuntary functions and contains both parasympathetic and sympathetic nerves. Choices A and B are incorrect as they do not fully capture the role of the ANS. While the ANS does control involuntary functions, this is a broader concept than just the reflex arc. While the ANS does contain motor (efferent) neurons, it also includes sensory (afferent) neurons, which are not specifically mentioned in the question. Therefore, choice C is not fully accurate. Choice D provides the most accurate and comprehensive description of the autonomic nervous system by highlighting its components, the parasympathetic and sympathetic nerves, which work together to regulate various bodily functions.

Correct Answer: A

Rationale: The correct answer is A: The renal pelvis. The renal pelvis serves as a reservoir for urine collected from the kidney's numerous collecting tubules, funneling it into the ureters for transport to the bladder. The renal cortex is the outer region of the kidney involved in filtration, while the renal medulla is the inner region responsible for concentrating urine. Bowman's capsule is part of the nephron and is involved in the initial filtration of blood in the kidney, not in funneling urine to the ureters.

Correct Answer: B

Rationale: The correct answer is B, the pelvic cavity. The pelvic cavity houses organs related to the urinary and reproductive systems. The urinary bladder, urethra, and ureters are located in the pelvic cavity, making it the correct choice. The thoracic cavity contains the heart and lungs, while the abdominal cavity houses organs like the stomach and intestines. The spinal cavity, on the other hand, protects the spinal cord. Therefore, options A, C, and D are incorrect as they do not house the specific organs mentioned in the question.

Correct Answer: B

Rationale: An amphoteric substance can act as both an acid or a base depending on the environment. It can donate a proton (act as an acid) or accept a proton (act as a base), showing versatility in its behavior. Choice A is incorrect as it describes an electrolyte rather than an amphoteric substance. Choice C is incorrect as it defines an acid based on the Br¸nsted-Lowry Acid-Base Theory. Choice D is incorrect as it specifically refers to a substance donating a proton in a neutralization reaction, not capturing the dual behavior of an amphoteric substance.

Correct Answer: A

Rationale: The correct answer is A, Merkel's discs. Merkel's discs are touch receptors that respond to light touch and slower vibrations, making them ideal for detecting subtle tactile stimuli. Pacinian corpuscles are specialized in detecting deep pressure and high-frequency vibrations, not light touch or slower vibrations. Meissner's corpuscles, on the other hand, are sensitive to light touch and low-frequency vibrations, but they do not specifically respond to slower vibrations. Ruffini endings are responsible for detecting skin stretch and continuous touch pressure, differentiating them from Merkel's discs, which are specifically attuned to light touch and slower vibrations.