Nursing Elites

1. What is the fatty sheath that insulates some nerve fibers and speeds up signal transmission called?

• A. Myelin sheath
• B. Dura mater
• C. Pia mater
• D. Arachnoid mater

Correct answer: A

Rationale: The correct answer is A: Myelin sheath. The myelin sheath is a fatty layer that surrounds and insulates some nerve fibers, facilitating the rapid transmission of signals along the nerve fibers. Choices B, C, and D (Dura mater, Pia mater, and Arachnoid mater) are layers of the meninges, protective membranes that surround the brain and spinal cord. The primary function of the meninges is to protect and support the central nervous system, not to insulate nerve fibers for signal transmission.

2. What is the principle behind the phenomenon of refraction, where waves bend when entering a new medium?

• A. Change in wavelength
• B. Change in frequency
• C. Change in wave speed
• D. None of the above

Correct answer: C

Rationale: Refraction occurs due to a change in wave speed when waves enter a new medium. As waves travel from one medium to another, their speed changes, causing them to bend. This change in speed is responsible for the bending of waves during refraction. It is not the change in wavelength or frequency that causes refraction, but rather the change in speed as waves move through different mediums. Therefore, the correct answer is the change in wave speed (Choice C). Choices A and B are incorrect as refraction is not primarily influenced by changes in wavelength or frequency, but by changes in wave speed. Choice D is also incorrect as there is a specific principle, which is the change in wave speed, behind the phenomenon of refraction.

3. A dietitian wants to convince a patient to lose weight. Which statement below best communicates a scientific argument that justifies the need for weight loss?

• A. Losing weight can lower blood pressure, increase energy levels, and promote overall health.
• B. Society tends to treat overweight people unfairly.
• C. Members of the opposite sex are more interested in people who maintain a healthy weight.
• D. Losing weight is easy to do.

Correct answer: A

Rationale: Choice A is the correct answer as it provides a scientific argument supported by evidence. Losing weight has been shown to lower blood pressure, increase energy levels, and promote overall health. These are concrete health benefits that can be objectively measured and monitored. Choices B and C do not offer scientific justifications for weight loss but rather focus on societal perceptions and personal relationships. Choice D is incorrect as losing weight is not always easy and may require significant effort and lifestyle changes.

4. Which of the following substances is a common base found in household products?

• A. Sodium chloride (NaCl)
• B. Ammonia (NH₃)
• C. Vinegar
• D. Lemon juice

Correct answer: B

Rationale: The correct answer is B, Ammonia (NH₃). Ammonia is commonly found in household products and is used in cleaning agents due to its alkaline properties. Sodium chloride (NaCl) is a common salt and not a base. Vinegar is acetic acid, which is acidic in nature. Lemon juice contains citric acid, making it acidic as well. Therefore, ammonia is the only base among the choices provided.

5. What is the shape of the DNA molecule?

• A. Linear
• B. Circular
• C. Double helix
• D. Straight chain

Correct answer: C

Rationale: The correct answer is C: Double helix. The shape of the DNA molecule is a double helix, a structure first described by James Watson and Francis Crick in 1953. This shape consists of two strands twisted around each other in a spiral. The double helix structure allows DNA to be compactly stored within the cell nucleus and provides stability to the molecule. Options (A) Linear, (B) Circular, and (D) Straight chain are incorrect as they do not accurately represent the shape of the DNA molecule. DNA is not linear but rather forms a twisted double helix; it is not circular like a ring but has a spiral structure, and it is not a straight chain but a twisted ladder-like structure.

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