What is the molarity of a solution made by dissolving 4.0 grams of NaCl into enough water to make 120 mL of solution? The atomic mass of Na is 23.0 g/mol, and Cl is 35.5 g/mol.

Correct Answer: B

Rationale: To find the molarity, first calculate the moles of NaCl. Moles of NaCl = 4.0 g / (23.0 g/mol + 35.5 g/mol) = 0.068 mol. Next, use the formula for molarity: Molarity = moles of solute / liters of solution. Molarity = 0.068 mol / 0.120 L = 0.57 M. Therefore, the molarity of the solution is 0.57 M. Choice A, 0.34 M, is incorrect as it does not match the calculated molarity. Choice C, 0.034 M, is incorrect as it is a decimal point off from the correct molarity. Choice D, 0.057 M, is incorrect as it does not match the calculated molarity of 0.57 M.

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.

Correct Answer: A

Rationale: Mitosis is the correct answer. It is the process of cell division in somatic cells, leading to the formation of two identical daughter cells with the same number of chromosomes as the parent cell. Meiosis, on the other hand, is the type of cell division that occurs in sex cells, leading to the formation of gametes with half the number of chromosomes. Respiration is a completely different biological process related to energy production, and cytogenesis is not a recognized term for cell division.

Correct Answer: B

Rationale: To find the molarity, first calculate the moles of NaCl. Moles of NaCl = 4.0 g / (23.0 g/mol + 35.5 g/mol) = 0.068 mol. Next, use the formula for molarity: Molarity = moles of solute / liters of solution. Molarity = 0.068 mol / 0.120 L = 0.57 M. Therefore, the molarity of the solution is 0.57 M. Choice A, 0.34 M, is incorrect as it does not match the calculated molarity. Choice C, 0.034 M, is incorrect as it is a decimal point off from the correct molarity. Choice D, 0.057 M, is incorrect as it does not match the calculated molarity of 0.57 M.

Correct Answer: B

Rationale: The correct answer is B, a neutralization reaction. In a neutralization reaction, an acid and a base react to produce a salt and water. This process involves the combination of H+ ions from the acid and OH- ions from the base to form water, while the remaining ions combine to form a salt. Therefore, a neutralization reaction is the specific type of chemical reaction that produces a salt. Choices A, C, and D are incorrect. An oxidation reaction involves the loss of electrons, a synthesis reaction involves the formation of a compound from simpler substances, and a decomposition reaction involves the breakdown of a compound into simpler substances. None of these reactions directly lead to the production of a salt, making them incorrect choices in this context.

Correct Answer: C

Rationale: The correct answer is C: Oxygen. Small, non-polar molecules like oxygen can easily pass through the cell membrane by passive transport as they move down their concentration gradient without the need for energy input. Complex sugars (choice A) are typically too large to pass through the membrane by passive transport. Non-lipid soluble molecules (choice B) may require active transport mechanisms. Choice D describes active transport, where molecules move against their concentration gradient, requiring energy input.

Correct Answer: C

Rationale: Sperm maturation occurs in the epididymis, a coiled tube located on the back of each testicle. In the epididymis, sperm gain motility and the ability to fertilize an egg. It serves as a storage site for mature sperm until ejaculation. The seminal vesicles and the prostate gland contribute fluids to semen, enhancing sperm viability and motility. The vas deferens is responsible for transporting mature sperm from the epididymis to the urethra during ejaculation, but it is not where sperm maturation takes place. Therefore, the correct answer is the epididymis.

Correct Answer: C

Rationale: The correct function of the sinuses is to warm, humidify, and filter the air we breathe. Sinuses play a crucial role in preparing the air for the respiratory system by adding moisture, warmth, and filtering out particles. Choice A is incorrect because while sinuses can help filter some particles, their primary function is not to trap pathogens. Choice B is incorrect as the sinuses do not control the direction of air down the trachea; this is regulated by the epiglottis and vocal cords. Choice D is incorrect as sinuses do not sweep pathogens away or direct them towards the trachea; instead, they condition the air for respiration.

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.