Nursing Elites

1. Which of the following is a chief difference between evaporation and boiling?

• A. Liquids boil only at the surface, while they evaporate equally throughout the liquid.
• B. Evaporating substances change from liquid to gas, while boiling substances change from gas to liquid.
• C. Evaporation can happen below a liquid's boiling point.
• D. Evaporation happens in nature, while boiling is a man-made phenomenon.

Correct answer: C

Rationale: The chief difference between evaporation and boiling is that evaporation can happen below a liquid's boiling point, while boiling only occurs at the liquid's boiling point. Evaporation is the process of a liquid turning into a gas at any temperature, while boiling specifically refers to the rapid vaporization that occurs when a liquid reaches its boiling point. Choice A is incorrect because liquids evaporate throughout the liquid, not just at the surface. Choice B is incorrect as evaporating substances change from liquid to gas, while boiling substances change from liquid to gas. Choice C is incorrect as boiling is not a man-made phenomenon; in fact, it is a natural process based on temperature changes. Choice D is incorrect because evaporation can happen naturally and is not limited to man-made processes.

2. What is the structure and function of elastic arteries?

• A. They are the smallest arteries and constrict and dilate frequently.
• B. They are medium-sized arteries that distribute blood to various organs.
• C. They are the largest arteries and stretch and recoil to accommodate blood pressure changes.
• D. They are thin-walled arteries that supply blood to the capillaries.

Correct answer: C

Rationale: The corrected answer is C. Elastic arteries, like the aorta, are the largest arteries in the body. They possess elastic fibers in their walls, allowing them to stretch and recoil in response to the pulsatile nature of blood flow from the heart. This elasticity helps to maintain blood pressure by absorbing the pressure waves generated by the heart's contractions and ensuring continuous blood flow to the organs. Choices A, B, and D are incorrect because elastic arteries are not the smallest arteries, do not constrict and dilate frequently, are not medium-sized arteries for distributing blood to various organs, and are not thin-walled arteries supplying blood to capillaries. Elastic arteries have a specific structure and function related to their ability to accommodate blood pressure changes due to their elastic properties, which is essential for the cardiovascular system's proper functioning.

3. Which of the following blood proteins can destroy pathogens?

• A. Complement system
• B. Fibrinogen
• C. Major histocompatibility complex
• D. Platelets

Correct answer: A

Rationale: The correct answer is A: Complement system. The complement system is a vital component of the immune system responsible for destroying pathogens through various mechanisms like promoting inflammation, enhancing phagocytosis, and directly lysing pathogens. Fibrinogen is crucial for blood clotting, the major histocompatibility complex is involved in immune responses, and platelets aid in blood clotting and wound healing. However, none of these directly destroy pathogens as the complement system does.

4. What is the process of separating a mixture based on the different boiling points of its components called?

• A. Filtration
• B. Chromatography
• C. Distillation
• D. Centrifugation

Correct answer: C

Rationale: Distillation is the process of separating a mixture based on the different boiling points of its components. During distillation, the mixture is heated to vaporize the component with the lowest boiling point first. The vapor is then cooled and condensed back into a liquid, allowing for the collection of fractions with different boiling ranges. This technique is effective for separating components that have significantly different boiling points. Filtration (Choice A) is a method used to separate solids from liquids or gases using a filter medium. Chromatography (Choice B) is a technique used to separate components of a mixture based on their differential affinities to a stationary phase and a mobile phase. Centrifugation (Choice D) is a process of separating particles from a solution based on differences in size, shape, density, and viscosity by spinning the mixture at high speeds.

5. Which of the following is an example of adaptive immunity?

• A. Inflammation
• B. Fever
• C. Antibodies
• D. Phagocytosis

Correct answer: C

Rationale: Antibodies are produced by the adaptive immune system in response to specific antigens. They play a crucial role in targeting and neutralizing pathogens, providing long-lasting immunity against future infections. In contrast, options A (inflammation), B (fever), and D (phagocytosis) are examples of innate immunity, the body's immediate, non-specific defense mechanisms. Inflammation is a response to tissue damage, fever is a systemic response to infection, and phagocytosis is a process where cells engulf and digest pathogens, all part of the innate immune response.

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