Nursing Elites

1. Which of the following structures is responsible for filtering lymph and supporting the immune system?

• A. Kidneys
• B. Lymph nodes
• C. Pancreas
• D. Liver

Correct answer: B

Rationale: Lymph nodes are responsible for filtering lymph and supporting the immune system. They contain immune cells that trap and destroy pathogens, making them crucial in immune response. The other choices, kidneys, pancreas, and liver, do not play a direct role in filtering lymph or supporting the immune system. The kidneys filter blood to remove waste and regulate electrolytes, the pancreas is involved in digestion and blood sugar regulation, and the liver is primarily responsible for detoxification and metabolism.

2. What are the differences between RNA and DNA?

• A. Both have the same structure and function.
• B. RNA is single-stranded, while DNA is double-stranded.
• C. RNA contains ribose sugar, while DNA contains deoxyribose sugar.
• D. RNA has adenine and guanine, while DNA has thymine and cytosine.

Correct answer: B

Rationale: A) This statement is incorrect. RNA and DNA have different structures and functions. RNA is involved in protein synthesis and other cellular processes, while DNA stores genetic information. B) This statement is correct. RNA is typically single-stranded, while DNA is double-stranded, forming a double helix structure. C) This statement is correct. RNA contains ribose sugar in its backbone, while DNA contains deoxyribose sugar. D) This statement is incorrect. RNA contains adenine, guanine, cytosine, and uracil, while DNA contains adenine, guanine, cytosine, and thymine. Choice B is the correct answer as it accurately describes one of the key differences between RNA and DNA, emphasizing their structural disparity in terms of single-strandedness for RNA and double-strandedness for DNA. Choices A, C, and D contain inaccuracies regarding the structural and compositional distinctions between RNA and DNA, making them incorrect choices.

3. A 10 kg box rests on a frictionless surface. A horizontal force of 20 N is applied to the box. What is the box's acceleration?

• A. 0.5 m/s²
• B. 1 m/s²
• C. 2 m/s²
• D. 10 m/s²

Correct answer: B

Rationale: The acceleration of an object is given by the formula \(a = \frac{F}{m}\), where \(F\) is the net force acting on the object and \(m\) is the mass of the object. In this case, the net force acting on the box is 20 N, and the mass of the box is 10 kg. Plugging these values into the formula, we get \(a = \frac{20}{10} = 2\) m/s².

4. A car is moving in a circle at a constant speed. Which of the following is NOT true about its motion?

• A. It has a constant centripetal acceleration
• B. Its tangential velocity remains constant
• C. It experiences a force directed towards the center of the circle
• D. It covers the same distance in equal time intervals along its circular path

Correct answer: B

Rationale: In circular motion at a constant speed, the car has a constant centripetal acceleration (choice A), experiences a force directed towards the center of the circle (choice C), and covers the same distance in equal time intervals along its circular path (choice D). However, the tangential velocity of an object in circular motion at a constant speed changes continuously as it moves around the circle, so it is not constant (choice B). The change in tangential velocity allows the car to maintain its motion in a circular path despite moving at a constant speed. Choice A is incorrect because centripetal acceleration is indeed present to keep the car moving in a circular path. Choice C is incorrect as a force towards the center is required to keep the car in circular motion. Choice D is incorrect because the car covers equal distances in equal time intervals to maintain its circular trajectory.

5. What phenomenon occurs when a wave encounters a change in medium causing a change in its speed and direction?

• A. Refraction
• B. Reflection
• C. Diffraction
• D. Interference

Correct answer: A

Rationale: Refraction is the phenomenon that occurs when a wave encounters a change in medium, causing a change in its speed and direction. This change in speed and direction is due to the wave bending as it passes from one medium to another with a different density. It is essential to understand refraction as it plays a crucial role in various phenomena, such as the bending of light in lenses, the formation of rainbows, and the way seismic waves travel through the Earth's layers. Reflection, while also a wave phenomenon, involves the bouncing back of a wave when it encounters a boundary. Diffraction refers to the bending of waves around obstacles or through openings, and interference involves the combination of two or more waves to form a new wave pattern.

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