Nursing Elites

1. Which of the following is the primary physical barrier the body uses to prevent infection?

• A. mucus membranes
• B. stomach acid
• C. skin
• D. urine

Correct answer: C

Rationale: The correct answer is 'C: skin.' The skin is the primary physical barrier the body uses to prevent infection. It acts as a protective shield that prevents harmful microorganisms from entering the body. The outer layer of the skin, known as the epidermis, acts as a tough physical barrier that blocks the entry of pathogens. Additionally, the skin has special immune cells that can help fight off invaders that manage to breach the physical barrier. Choices A, B, and D are incorrect. While mucous membranes, stomach acid, and urine play important roles in the body's defense against pathogens, the primary physical barrier is the skin, which covers the entire body and provides a robust protective barrier.

2. How are kidney stones formed?

• A. Due to excess water not being reabsorbed
• B. When minerals crystallize in the urine
• C. When electrolytes become too concentrated
• D. All of the above

Correct answer: B

Rationale: Kidney stones are formed when minerals in the urine crystallize and stick together to form solid masses. Excess water not being reabsorbed (option A) does not directly contribute to kidney stone formation. Similarly, electrolytes becoming too concentrated (option C) is not a direct cause of kidney stone formation. The correct answer is B because the crystallization of minerals in the urine leads to the formation of kidney stones.

3. Which orbital can hold a maximum of 8 electrons?

• A. s orbital
• B. p orbital
• C. d orbital
• D. f orbital

Correct answer: B

Rationale: The correct answer is the p orbital. Each p orbital can hold a maximum of 6 electrons (2 electrons in each of the 3 p orbitals), totaling 18 possible electrons when considering all three p orbitals. The s orbital can hold a maximum of 2 electrons, the d orbital can hold a maximum of 10 electrons, and the f orbital can hold a maximum of 14 electrons. Therefore, the p orbital is the orbital that can hold a maximum of 8 electrons, making it the correct choice.

4. What is the role of hemoglobin in the human body?

• A. Transport oxygen in red blood cells
• B. Bind oxygen to red blood cells
• C. Carry carbon dioxide from tissues to lungs
• D. Help red blood cells transport oxygen

Correct answer: D

Rationale: The correct answer is D: 'Help red blood cells transport oxygen.' Hemoglobin acts as a carrier molecule in red blood cells, binding to oxygen in the lungs and releasing it in the tissues. It facilitates the transport of oxygen from the lungs to the tissues and aids in returning carbon dioxide from the tissues to the lungs. Choices A, B, and C are incorrect because hemoglobin itself does not transport oxygen independently or bind oxygen to red blood cells nor does it carry carbon dioxide from tissues to lungs; instead, it assists red blood cells in the transportation of oxygen.

5. What is the process of combining two or more substances to form a heterogeneous mixture called?

• A. Dissolving
• B. Diluting
• C. Mixing
• D. Reacting

Correct answer: C

Rationale: The correct answer is 'Mixing.' When substances are combined, a heterogeneous mixture is formed where the components are physically distinguishable. 'Dissolving' (Choice A) is the process of a solute becoming uniformly dispersed in a solvent to form a solution, not a heterogeneous mixture. 'Diluting' (Choice B) refers to reducing the concentration of a solute in a solution. 'Reacting' (Choice D) involves a chemical change where substances interact to form new products, rather than just physically mixing to form a heterogeneous mixture.

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