Nursing Elites

1. What is the primary function of the liver in the digestive system?

• A. To absorb water
• B. To produce bile
• C. To store glucose
• D. To regulate metabolism

Correct answer: B

Rationale: The liver's main function in the digestive system is to produce bile. Bile helps in the digestion and absorption of fats by emulsifying them, breaking down large fat globules into smaller droplets that can be acted upon by digestive enzymes. Choices A, C, and D are incorrect because the liver's primary role in the digestive system is not to absorb water, store glucose, or regulate metabolism. While the liver does have roles in metabolism and glucose regulation, its key function in digestion is bile production.

2. How many moles of oxygen are required to completely react with 5 moles of propane (C3H8) in the combustion reaction?

• A. 5 moles
• B. 10 moles
• C. 15 moles
• D. 20 moles

Correct answer: C

Rationale: In the balanced chemical equation for the combustion of propane (C3H8): C3H8 + 5O2 → 3CO2 + 4H2O, 1 mole of propane (C3H8) reacts with 5 moles of oxygen (O2). To determine the moles of oxygen required to react with 5 moles of propane, we use the molar ratio: 5 moles propane x 5 moles oxygen / 1 mole propane = 25 moles oxygen. However, since the question specifically asks for the moles of oxygen needed to react with 5 moles of propane, the correct answer is 15 moles of oxygen. Choice A, 5 moles, is incorrect because this is the amount of propane provided, not the oxygen required. Choice B, 10 moles, is incorrect as it does not correspond to the molar ratio in the balanced equation. Choice D, 20 moles, is incorrect as it is not in line with the stoichiometry of the reaction.

3. Which of these body parts does not contain melanin?

• A. Hair
• B. Nails
• C. Skin
• D. Iris

Correct answer: D

Rationale: The iris is the colored part of the eye that determines the eye's color. Melanin is not present in the iris, unlike hair, nails, and skin. Melanin gives color to hair, nails, and skin, but not to the iris. Therefore, the correct answer is the iris (Choice D). Choices A, B, and C contain melanin and are incorrect.

4. When making a dilution, what do you do?

• A. Add more solvent to a concentrated solution
• B. Change the temperature of the solution
• C. Decrease the concentration of a solution
• D. All of the above

Correct answer: C

Rationale: When making a dilution, you decrease the concentration of a solution by adding more solvent to a concentrated solution. This process does not involve changing the temperature of the solution, so option B is incorrect. Option A is also incorrect because you are not adding more solute to the solution during dilution. Therefore, the correct answer is C) Decrease the concentration of a solution. Options A and B are incorrect as dilution involves adding more solvent, not solute, and does not require changing the temperature of the solution.

5. Which hormone, produced by the thyroid gland, regulates calcium levels in the blood by enhancing calcium absorption in the intestines and reducing calcium loss in the kidneys?

• A. Calcitonin
• B. Parathyroid hormone (PTH)
• C. Thyroxine
• D. Insulin

Correct answer: A

Rationale: Calcitonin is the hormone produced by the thyroid gland that regulates calcium levels in the blood. It enhances calcium absorption in the intestines and reduces calcium loss in the kidneys. Parathyroid hormone (PTH) operates oppositely to calcitonin by increasing calcium levels in the blood. Thyroxine is a thyroid gland hormone that primarily regulates metabolism, not calcium levels. Insulin, produced by the pancreas, is responsible for controlling blood sugar levels, not calcium levels. Therefore, the correct answer is Calcitonin as it specifically targets calcium regulation in the body.

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