Nursing Elites

1. What property of a substance refers to its ability to undergo a chemical change and form new substances with different properties?

• A. Density
• B. Mass
• C. Reactivity
• D. Volume

Correct answer: C

Rationale: Reactivity is the property of a substance that describes its ability to undergo a chemical change and form new substances with different properties. Density (A), mass (B), and volume (D) are physical properties of a substance and do not directly relate to its ability to undergo chemical changes. Density is mass per unit volume, mass is the amount of matter in a substance, and volume is the space occupied by a substance.

2. What phenomenon is responsible for the mirage effect seen in deserts?

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

Correct answer: B

Rationale: Refraction is the bending of light as it passes from one medium to another of different density. In deserts, the temperature gradient causes light to bend, creating the mirage effect where distant objects appear distorted or displaced. Diffraction refers to the bending of light around obstacles or apertures, not the cause of mirages. Interference involves the superposition of two or more waves, which is not the mechanism behind mirages. Polarization refers to the orientation of light waves in a specific plane and is not responsible for the mirage effect in deserts. Therefore, the correct answer is refraction.

3. Which of the following nutrients is essential for muscle growth and repair?

• A. Vitamin C
• B. Protein
• C. Carbohydrates
• D. Fat

Correct answer: B

Rationale: Protein is essential for muscle growth and repair as it provides the necessary building blocks (amino acids) for muscle tissue synthesis and repair. While vitamins and minerals are crucial for overall health, protein has a specific role in muscle development. Carbohydrates supply energy for workouts, and fats are important for general health but are less directly involved in muscle growth and repair compared to protein.

4. Fluorescent microscopy utilizes which property of certain molecules to create a visible image?

• A. Staining properties
• B. Light absorption
• C. Fluorescence emission
• D. Refraction

Correct answer: C

Rationale: Fluorescent microscopy relies on the property of certain molecules to fluoresce when exposed to specific wavelengths of light. When these molecules absorb light energy, they become excited and then emit light at a longer wavelength, producing a visible image. This emitted light is what is used to create the image in fluorescent microscopy, making option C, fluorescence emission, the correct answer. Staining properties (option A) are used to enhance contrast in microscopy but are not the primary mechanism in fluorescent microscopy. Light absorption (option B) is involved in the excitation of fluorescent molecules but is not the property used to create the visible image. Refraction (option D) is the bending of light as it passes through different mediums and is not the property utilized in fluorescent microscopy.

5. What is the main function of the skeletal system?

• A. To regulate blood pressure
• B. To protect internal organs
• C. To produce hormones
• D. To fight infection

Correct answer: B

Rationale: The main function of the skeletal system is to provide structural support for the body, protect internal organs, facilitate movement, and produce blood cells in the bone marrow. Choice A, 'To regulate blood pressure,' is incorrect as blood pressure regulation is primarily controlled by the circulatory and endocrine systems. Choice C, 'To produce hormones,' is incorrect as hormone production is mainly carried out by the endocrine system. Choice D, 'To fight infection,' is incorrect as the immune system is responsible for fighting infections, not the skeletal system.

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