Nursing Elites

1. Which of the following units is used to express concentration as a mass of solute per unit volume of solution?

• A. Molality (m)
• B. Molarity (M)
• C. Weight percent (%)
• D. Parts per million (ppm)

Correct answer: A

Rationale: Molality (m) is the unit used to express concentration as a mass of solute per unit volume of solution. It is calculated by dividing the mass of solute in grams by the mass of the solvent in kilograms. Molality is preferred over molarity when there are large temperature variations as it is temperature-independent, making it a more accurate measure of concentration. Molarity (B) is the unit used to express concentration as moles of solute per liter of solution, weight percent (C) is the mass of solute per 100 parts of the total mass of the solution, and parts per million (D) is used to express very small concentrations where 1 ppm is equivalent to 1 mg of solute per liter of solution.

2. Which element has the highest melting point of any element?

• A. Tungsten
• B. Iron
• C. Platinum
• D. Carbon

Correct answer: D

Rationale: Among the choices provided, carbon, in the form of diamond, has the highest melting point of any element. Diamond's strong covalent bonds between carbon atoms make it incredibly resistant to heat and pressure, giving it the highest melting point compared to tungsten, iron, and platinum. Tungsten is known for its high melting point among metals but not as high as carbon. Iron and platinum have lower melting points compared to carbon, making them incorrect choices in this context.

3. The term that refers to the specific role and position an organism occupies within an ecosystem is called a:

• A. Habitat
• B. Niche
• C. Population
• D. Biome

Correct answer: B

Rationale: A) Habitat refers to the specific physical environment where an organism lives, including the biotic and abiotic factors present. While the habitat is important for an organism's survival, it does not encompass the specific role and interactions of the organism within the ecosystem. B) Niche refers to the specific role and position an organism occupies within an ecosystem, including its interactions with other organisms and its physical environment. This includes the organism's feeding habits, behavior, preferred habitat, and how it obtains resources. The niche of an organism is crucial in determining its impact on the ecosystem and its relationships with other species. C) Population refers to a group of individuals of the same species living in a specific area and interacting with each other. While populations play a role in ecosystems, they do not specifically describe the role and position of an individual organism within the ecosystem. D) Biome refers to a large geographical area characterized by its climate, fauna, and flora. It is a broader concept than niche, habitat, or population, focusing on the overall characteristics of the environment rather than the specific role of an individual organism.

4. Which test is commonly used to assess kidney function?

• A. Complete blood count (CBC)
• B. Blood sugar test
• C. Urinalysis
• D. Creatinine clearance test

Correct answer: D

Rationale: The creatinine clearance test is commonly used to assess kidney function. Creatinine, a waste product produced by muscles, is filtered out of the blood by the kidneys. The creatinine clearance test measures how efficiently the kidneys clear creatinine from the blood. Abnormal levels of creatinine in the blood can indicate kidney dysfunction, making this test crucial for evaluating kidney function. Choice A, a complete blood count (CBC), provides information about different blood cells and is not a specific test for kidney function. Choice B, a blood sugar test, assesses glucose levels in the blood and is not directly related to kidney function. Choice C, a urinalysis, evaluates the contents of urine and can provide information about kidney health but is not as specific for assessing kidney function as the creatinine clearance test.

5. Which of the following types of immunity is provided by the secretion of antibodies by B-cells?

• A. Cell-mediated
• B. Humoral
• C. Innate immunity
• D. Phagocytic

Correct answer: B

Rationale: The correct answer is B: Humoral. Humoral immunity involves B-cells secreting antibodies to fight pathogens. In this type of immunity, antibodies circulate in the blood and other body fluids to neutralize pathogens and prevent infections. Cell-mediated immunity, on the other hand, involves the activation of T-cells to directly attack infected or abnormal cells, not the secretion of antibodies. Innate immunity refers to the nonspecific defense mechanisms the body has in place from birth, such as physical barriers and inflammatory responses. Phagocytic immunity is not a recognized type of immunity; phagocytosis is a mechanism used by cells like macrophages to engulf and digest pathogens, but it is not a specific form of immunity like humoral or cell-mediated immunity.

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