Nursing Elites

1. Which organ is responsible for filtering waste from the blood?

• A. Kidneys
• B. Pancreas
• C. Liver
• D. Heart

Correct answer: A

Rationale: The correct answer is A: Kidneys. The kidneys are responsible for filtering waste products from the blood, maintaining fluid and electrolyte balance. The pancreas aids in digestion and regulates blood sugar levels. The liver processes nutrients, detoxifies chemicals, and produces bile. The heart is responsible for pumping blood throughout the body. Choice B, Pancreas, is incorrect because the pancreas plays a role in digestion and blood sugar regulation, not in filtering waste from the blood. Choice C, Liver, is incorrect as the liver processes nutrients, detoxifies chemicals, and produces bile, but it is not primarily responsible for filtering waste from the blood. Choice D, Heart, is incorrect as the heart's main function is pumping blood throughout the body, not filtering waste from the blood.

2. What term describes the point where parallel rays of light converge or appear to diverge after passing through a lens or reflecting off a mirror?

• A. Aperture
• B. Focal length
• C. Refractive index
• D. Lens thickness

Correct answer: B

Rationale: The focal length is the term used to describe the point where parallel rays of light converge or appear to diverge after passing through a lens or reflecting off a mirror. It is a fundamental concept in optics that determines the behavior of light rays in optical systems. The focal length directly affects image formation, magnification, and focus. Options (A) Aperture, (C) Refractive index, and (D) Lens thickness are not specifically associated with the convergence or divergence of light rays in optical systems. Aperture refers to the opening through which light passes, refractive index is a measure of how much light bends when entering a medium, and lens thickness is unrelated to the convergence or divergence of light rays.

3. What is the role of RNA interference in silencing genes?

• A. Increases protein production
• B. Promotes gene mutation
• C. Inhibits the expression of specific genes
• D. Repairs damaged DNA

Correct answer: C

Rationale: RNA interference (RNAi) is a biological process that involves the silencing of gene expression by inhibiting the translation of mRNA or by degrading mRNA molecules. This mechanism plays a crucial role in regulating gene expression and can be used to selectively silence specific genes. By interfering with the expression of specific genes, RNAi can downregulate protein production from those genes. Therefore, option C, 'Inhibits the expression of specific genes,' is the correct role of RNA interference in silencing genes. Options A, B, and D are incorrect because RNA interference does not increase protein production, promote gene mutation, or repair damaged DNA; its primary function is to inhibit gene expression by degrading or interfering with mRNA.

4. What is the function of the lymphatic system?

• A. To transport oxygen
• B. To filter waste from the blood
• C. To produce red blood cells
• D. To regulate body temperature

Correct answer: B

Rationale: The correct answer is B: 'To filter waste from the blood.' The lymphatic system is responsible for draining excess fluid from tissues, absorbing fats from the digestive system, and filtering out harmful substances and waste products from the blood. It also plays a crucial role in the body's immune defense by transporting white blood cells and antibodies to fight off infections. Choices A, C, and D are incorrect because transporting oxygen, producing red blood cells, and regulating body temperature are functions performed by other systems in the body, such as the respiratory system, bone marrow, and thermoregulatory mechanisms, respectively.

5. What property of matter explains why ice floats on water?

• A. Viscosity
• B. Density
• C. Buoyancy
• D. Surface tension

Correct answer: C

Rationale: The correct answer is C, buoyancy. Ice floats on water due to buoyancy, a property of matter. When water freezes into ice, it becomes less dense than liquid water, causing it to float. This phenomenon occurs because the molecules in ice are more spread out compared to liquid water, resulting in ice being less dense and able to float on the surface. Choice A, viscosity, is incorrect because viscosity refers to a fluid's resistance to flow, not its ability to float. Choice B, density, is incorrect because while ice being less dense than water is the reason it floats, this choice does not explain the specific property that causes this phenomenon. Choice D, surface tension, is incorrect as it pertains to the cohesive forces between molecules at the surface of a liquid, not the reason why ice floats on water.

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