Nursing Elites

1. Which of the following blood proteins can destroy pathogens?

• A. Complement system
• B. Fibrinogen
• C. Major histocompatibility complex
• D. Platelets

Correct answer: A

Rationale: The correct answer is A: Complement system. The complement system is a vital component of the immune system responsible for destroying pathogens through various mechanisms like promoting inflammation, enhancing phagocytosis, and directly lysing pathogens. Fibrinogen is crucial for blood clotting, the major histocompatibility complex is involved in immune responses, and platelets aid in blood clotting and wound healing. However, none of these directly destroy pathogens as the complement system does.

2. An uncharged atom has an electron configuration of 1s2 2s2 2p6 3s2 and a mass number of 14. How many protons does it have?

• A. 14
• B. 6
• C. 8
• D. 12

Correct answer: B

Rationale: The correct answer is B (6 protons). The electron configuration provided corresponds to the element carbon, which has 6 protons. The mass number does not affect the number of protons in an atom, so despite the mass number of 14, the atom still contains 6 protons. Choice A (14) is incorrect because the mass number does not determine the number of protons. Choices C (8) and D (12) are incorrect as they do not match the number of protons in a carbon atom.

3. 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.

4. Which of the following nucleobases does not exist in RNA?

• A. Uracil
• B. Thymine
• C. Cytosine
• D. Guanine

Correct answer: B

Rationale: The correct answer is 'B: Thymine'. Thymine is a nucleobase found in DNA but is replaced by uracil in RNA. RNA contains Uracil, Cytosine, and Guanine as its nucleobases. Cytosine and Guanine are present in both DNA and RNA, while Thymine is exclusive to DNA and Uracil is specific to RNA.

5. What is the term for the gradual loss of topsoil due to wind or water erosion?

• A. Desertification
• B. Leaching
• C. Salinization
• D. Acidification

Correct answer: A

Rationale: A) Desertification is the correct term for the gradual loss of topsoil due to wind or water erosion. It refers to the process by which fertile land becomes desert, usually due to factors like drought, deforestation, or inappropriate agriculture practices. This process can lead to the degradation of land and contribute to the expansion of deserts. B) Leaching is the process in which minerals are washed out of the soil by water moving downwards through it. This is different from the loss of topsoil due to erosion. C) Salinization occurs when salt accumulates in the soil, typically as a result of irrigation in arid regions. While salinization affects soil quality, it is not specifically related to the gradual loss of topsoil due to erosion. D) Acidification refers to the decrease in soil pH, often caused by factors like acid rain or the use of acidic fertilizers. This process is distinct from the gradual loss of topsoil due to erosion.

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