Nursing Elites

1. When is a solution formed?

• A. One substance dissolves in another
• B. Two or more substances react chemically
• C. A solid changes to a liquid
• D. None of the above

Correct answer: A

Rationale: A solution is formed when one substance dissolves in another. This process creates a homogeneous mixture where the solute is dispersed in the solvent, resulting in a uniform composition throughout the mixture. Choice B is incorrect because chemical reactions involve the transformation of substances into new compounds, not the formation of solutions. Choice C is incorrect as it describes a physical change from a solid to a liquid, not the formation of a solution. Choice D is incorrect as one substance dissolving in another is the defining characteristic of a solution.

2. What is the main difference between white and brown adipose tissue?

• A. Location only
• B. Function and energy metabolism
• C. Color only
• D. Both white and brown have the same function

Correct answer: B

Rationale: The main difference between white and brown adipose tissue lies in their function and energy metabolism. White adipose tissue is primarily involved in energy storage, while brown adipose tissue is specialized for energy expenditure and thermogenesis. This functional disparity is the key dissimilarity between white and brown adipose tissue, rather than just their location or color. Choice A is incorrect because the difference is not only in location but also in function. Choice C is incorrect as color is not the defining factor in their distinction. Choice D is incorrect as white and brown adipose tissues serve different functions in the body.

3. What is the difference between a real image and a virtual image formed by a lens?

• A. Real images can be projected onto a screen, while virtual images cannot.
• B. Real images are always upright, while virtual images can be inverted.
• C. Real images are formed by converging lenses, while virtual images are formed by diverging lenses.
• D. All of the above are true.

Correct answer: A

Rationale: The correct answer is A. Real images can be projected onto a screen because they are formed by the actual convergence of light rays, while virtual images cannot be projected onto a screen as they appear to diverge from a point behind the lens. Real and virtual images do not have a consistent orientation (upright or inverted), so option B is incorrect. Real images are formed by both converging and diverging lenses depending on the specific scenario, so option C is not a definitive distinction. Option D is incorrect as not all the statements are true. Therefore, the only accurate general distinction between real and virtual images is that real images can be projected onto a screen, while virtual images cannot.

4. What is the name of the microscopic finger-like projections that increase the surface area for absorption in the small intestine?

• A. Goblet cells
• B. Paneth cells
• C. Villi
• D. Crypts of Lieberkühn

Correct answer: C

Rationale: A) Goblet cells: Goblet cells are specialized cells that secrete mucus to protect the lining of the digestive tract. While important for maintaining the health of the intestines, goblet cells do not increase the surface area for absorption in the small intestine. B) Paneth cells: Paneth cells are specialized cells found in the small intestine that secrete antimicrobial peptides. They play a role in protecting the intestinal stem cells and maintaining the gut microbiota balance, but they do not increase the surface area for absorption. C) Villi: Villi are microscopic finger-like projections found in the small intestine that increase the surface area available for absorption of nutrients. Each villus contains blood vessels and lacteals (lymphatic vessels) that help absorb nutrients from digested food. D) Crypts of Lieberkühn: Crypts of Lieberkühn are small pits located between the villi

5. What is the difference between a pure substance and a mixture?

• A. Pure substances have a fixed composition, mixtures don't.
• B. Mixtures have a fixed composition, pure substances don't.
• C. Pure substances can be in any state, mixtures are not always solids.
• D. Pure substances are always elements, mixtures are always compounds.

Correct answer: A

Rationale: Pure substances have a definite and constant composition, meaning they are made up of only one type of atom or molecule with fixed proportions. This composition does not vary. On the other hand, mixtures are composed of two or more substances physically combined. The components of a mixture can be present in varying proportions, leading to a variable composition. Choice A is correct as it accurately distinguishes between pure substances and mixtures based on the fixed composition of pure substances and the variable composition of mixtures. Choice B is incorrect because mixtures, not pure substances, have variable compositions. Choice C is incorrect as both pure substances and mixtures can exist in different states. Choice D is incorrect because pure substances can be compounds as well, not exclusively elements, and mixtures can contain elements and compounds.

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