Nursing Elites

1. Which force opposes the relative motion between surfaces in contact?

• A. Tension force
• B. Frictional force
• C. Gravitational force
• D. Magnetic force

Correct answer: b

Rationale: Friction is the force that opposes motion between surfaces in contact.

2. Which of the following best describes a balanced force acting on an object?

• A. The object remains at rest
• B. The object moves with constant velocity
• C. The object accelerates
• D. The object's mass changes

Correct answer: b

Rationale: When balanced forces act on an object, the object remains in a state of constant velocity (including at rest).

3. During gas exchange in the alveoli, what happens to oxygen?

• A. Oxygen is released from the bloodstream into the alveoli.
• B. Oxygen is absorbed from the alveoli into the bloodstream.
• C. Oxygen is converted into carbon dioxide.
• D. Oxygen is stored in the alveoli for later use.

Correct answer: B

Rationale: During gas exchange in the alveoli, oxygen is absorbed from the alveoli into the bloodstream. In the alveoli, oxygen diffuses across the thin walls of the alveoli and into the surrounding capillaries where it binds to hemoglobin in red blood cells. This oxygen-rich blood is then transported to the body's tissues for cellular respiration. Therefore, option B is correct as it accurately describes the direction of oxygen movement during the process of gas exchange in the lungs.

4. What is the name of the regulatory region in a gene that controls its expression?

• A. Exon
• B. Intron
• C. Promoter
• D. Enhancer

Correct answer: C

Rationale: Rationale: A) Exon: Exons are the coding regions of a gene that are transcribed into mRNA and eventually translated into proteins. Exons do not regulate gene expression. B) Intron: Introns are non-coding regions of a gene that are removed during RNA processing and do not play a direct role in controlling gene expression. C) Promoter: The promoter is a regulatory region located at the beginning of a gene that initiates the process of transcription by binding transcription factors and RNA polymerase. It plays a crucial role in controlling gene expression. D) Enhancer: Enhancers are regulatory regions that can be located far from the gene they regulate and can increase the transcription of a gene. While enhancers are important for gene expression, the specific region that controls gene expression is the promoter. Therefore, the correct answer is C) Promoter, as it is the regulatory region in a gene that controls its expression by initiating transcription.

5. B cells in the immune system are responsible for:

• A. Directly attacking and engulfing pathogens
• B. Producing antibodies specific to a pathogen
• C. Destroying infected body cells
• D. All of the above

Correct answer: B

Rationale: B cells in the immune system are responsible for producing antibodies specific to a pathogen. This is because B cells are a type of white blood cell that play a crucial role in the adaptive immune response. When a B cell encounters a specific pathogen, it differentiates into plasma cells that produce antibodies targeted against that particular pathogen. These antibodies then tag the pathogen for destruction by other immune cells. B cells do not directly attack and engulf pathogens like phagocytes, nor do they destroy infected body cells like cytotoxic T cells. Therefore, option B is the correct answer as it accurately reflects the primary function of B cells in the immune system.

6. Which property of matter explains why ice floats on water?

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

Correct answer: c

Rationale: Buoyancy is the upward force exerted by a fluid (like water) on an object immersed in it. Ice floats on water because it is less dense than water, experiencing an upward force (buoyancy) greater than its weight.

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