Nursing Elites

1. What is the body's primary defense against pathogens?

• A. Phagocytes
• B. Antibodies
• C. Memory B cells
• D. T lymphocytes

Correct answer: A

Rationale: The correct answer is A: Phagocytes. Phagocytes are the body's first line of defense against pathogens. They are innate immune cells that engulf and digest foreign particles like bacteria and viruses, preventing infections. Phagocytes act as the initial barrier to invading pathogens and are part of the innate immune response. Choice B, Antibodies, are produced by B cells in the adaptive immune response. Choice C, Memory B cells, are also part of the adaptive immune response and provide a faster and stronger response upon re-exposure to pathogens. Choice D, T lymphocytes, are part of the adaptive immune response, particularly involved in cell-mediated immunity.

2. Which human body system is correctly matched with its function?

• A. Respiratory system; exchanges oxygen and carbon dioxide in the lungs.
• B. Circulatory system; transports oxygen to cells and removes carbon dioxide.
• C. Lymphatic system; produces antibodies that destroy virally affected or foreign cells.
• D. Endocrine system; regulates hormones controlling bodily functions and metabolism.

Correct answer: B

Rationale: The circulatory system is responsible for the transportation of oxygen from the lungs to all the body's cells and tissues, as well as removing carbon dioxide from the cells and transporting it back to the lungs to be exhaled. This process is crucial for cellular respiration and the exchange of gases necessary for bodily functions. Choice B accurately matches the role of the circulatory system by describing its function of transporting oxygen to cells and removing carbon dioxide, which is essential for maintaining proper cellular activities. Choices A, C, and D are incorrect because they do not accurately match the body system with its function. The respiratory system primarily involves the exchange of gases in the lungs, not transportation to cells; the lymphatic system deals with immunity through the production of antibodies, not gas exchange; and the endocrine system's main function is hormone regulation, not the transport of gases.

3. Which of the following is an example of a nonpolar solvent?

• A. Water
• B. Ethanol
• C. Acetone
• D. Hydrochloric acid

Correct answer: B

Rationale: - Water (option A) is a polar solvent due to its uneven distribution of charge, with the oxygen atom being partially negative and the hydrogen atoms being partially positive. - Ethanol (option B) is a nonpolar solvent because it has a symmetrical molecular structure that does not result in significant charge separation. - Acetone (option C) is a polar solvent as it contains a carbonyl group that results in a partial negative charge on the oxygen atom. - Hydrochloric acid (option D) is a polar solvent due to the presence of the highly electronegative chlorine atom, which results in a partial negative charge.

4. The largest level of ecological organization is a:

• A. Population
• B. Community
• C. Ecosystem
• D. Biome

Correct answer: D

Rationale: A) Population: A population consists of individuals of the same species living in the same area. It is a smaller level of ecological organization compared to a biome. B) Community: A community consists of populations of different species living and interacting in the same area. It is a larger level of organization than a population but smaller than an ecosystem or biome. C) Ecosystem: An ecosystem includes all living organisms (biotic factors) and their physical environment (abiotic factors) interacting in a particular area. It is a larger level of organization than a community but smaller than a biome. D) Biome: The correct answer is D - Biome. A biome is the largest level of ecological organization and encompasses a large geographic area characterized by a specific climate, vegetation, and animal life. Biomes can be found on multiple continents and are defined by similar abiotic and biotic factors. Therefore, it is the largest level of ecological organization among the options provided, making it the correct answer.

5. How does the respiratory system facilitate gas exchange between air and blood?

• A. Diffusion
• B. Exhalation
• C. Inspiration
• D. Ventilation

Correct answer: A

Rationale: The correct answer is 'Diffusion.' Diffusion is the process by which gases are exchanged between air in the alveoli and blood in the capillaries. Oxygen moves from the alveoli into the blood, while carbon dioxide moves from the blood into the alveoli through diffusion. Exhalation is the process of expelling air from the lungs, inspiration is the process of inhaling air into the lungs, and ventilation refers to the overall movement of air in and out of the lungs. While these processes are essential for the respiratory system to function, they are not directly responsible for the gas exchange between air and blood, which is primarily achieved through diffusion.

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