Nursing Elites

1. Which element is used in fire extinguishers to smother flames by displacing oxygen?

• A. Nitrogen
• B. Carbon dioxide
• C. Helium
• D. Argon

Correct answer: B

Rationale: Carbon dioxide extinguishes flames by depriving them of oxygen, preventing the chemical reaction that sustains the fire.

2. Saliva contains an enzyme that breaks down carbohydrates. What is the name of this enzyme?

• A. Pepsin
• B. Amylase
• C. Lipase
• D. Trypsin

Correct answer: B

Rationale: The correct answer is B: Amylase. Saliva contains the enzyme amylase, which is responsible for breaking down carbohydrates into simpler sugars like maltose and glucose. Pepsin (A) is an enzyme found in the stomach that breaks down proteins. Lipase (C) is an enzyme that breaks down fats, and trypsin (D) is another enzyme that breaks down proteins, but both of these are not found in saliva. Knowing the function of amylase in saliva helps in the digestion of carbohydrates, making it the correct answer.

3. A concave mirror can be used to:

• A. Focus light to a single point
• B. Only create virtual images
• C. Always magnify objects
• D. Scatter light

Correct answer: A

Rationale: A concave mirror can be used to focus light to a single point because of its reflective surface that curves inward. When light rays parallel to the mirror's principal axis strike the mirror, they converge at a focal point, creating a real image. This property makes concave mirrors useful in applications like reflecting telescopes and headlights, where focusing light to a point is necessary for proper functioning. Virtual images are also created by concave mirrors, but the primary function is to focus light rather than create virtual images. Magnification of objects and scattering of light are not inherent properties of concave mirrors.

4. A hypothesis should be:

• A. A definitive statement of fact based on existing knowledge.
• B. A testable prediction based on observations and reasoning.
• C. A broad question without any specific direction or focus.
• D. A personal belief or opinion not requiring further investigation.

Correct answer: B

Rationale: Hypotheses guide scientific exploration by providing a framework for testing potential explanations.

5. Which of the following is the smallest unit of matter?

• A. Molecule
• B. Atom
• C. Compound
• D. Element

Correct answer: B

Rationale: An atom is the fundamental building block of matter, while molecules are formed by the combination of atoms.

6. The main function of the nephrons is to:

• A. Store urine
• B. Filter blood and remove waste products
• C. Produce hormones
• D. Control blood pressure

Correct answer: B

Rationale: The correct answer is B: 'Filter blood and remove waste products.' Nephrons are the functional units of the kidneys responsible for filtering blood to remove waste products, excess ions, and water, while reabsorbing essential substances like glucose and amino acids. This process forms urine, which is stored in the bladder before being excreted. Options A, C, and D are incorrect because nephrons do not store urine, produce hormones, or directly control blood pressure; although the kidneys do play a role in long-term blood pressure regulation through mechanisms like the renin-angiotensin-aldosterone system.

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