Nursing Elites

1. Which nitrogenous bases pair with each other in DNA?

• A. A-G and T-C
• B. A-T and C-G
• C. A-T and T-T
• D. C-C and G-G

Correct answer: B

Rationale: In DNA, nitrogenous bases pair with each other in a specific manner known as complementary base pairing. Adenine (A) always pairs with Thymine (T), and Cytosine (C) always pairs with Guanine (G). This pairing is essential for maintaining the structure and function of DNA. Option B is the correct answer as it correctly identifies the nitrogenous bases that pair with each other in DNA. Choices A, C, and D are incorrect because they do not follow the established base pairing rules in DNA. A-T and C-G are the complementary base pairs in DNA, ensuring the stability and replication fidelity of the genetic material.

2. Decomposers in an ecosystem play a vital role by:

• A. Photosynthesizing and producing organic matter
• B. Breaking down dead organisms and returning nutrients to the environment
• C. Preying on herbivores and controlling their populations
• D. Fixing nitrogen from the atmosphere and making it available to plants

Correct answer: B

Rationale: Decomposers are organisms that break down dead organic matter, such as dead plants and animals, into simpler substances. By doing so, they help to recycle nutrients back into the environment, making them available for other organisms to use. This process is essential for the functioning of ecosystems, as it ensures that nutrients are not lost but instead are continuously cycled through the ecosystem. Photosynthesis (option A) is the process by which plants and some other organisms convert light energy into chemical energy in the form of glucose, and it is not a role of decomposers. Preying on herbivores (option C) is a role typically carried out by predators, not decomposers. Fixing nitrogen from the atmosphere (option D) is a process carried out by nitrogen-fixing bacteria, not decomposers.

3. What is the term for the time it takes for a wave to complete one full cycle?

• A. Frequency
• B. Amplitude
• C. Period
• D. Wavelength

Correct answer: C

Rationale: The period of a wave is the time it takes for one complete cycle to occur. It is the duration between two successive points in the wave that are in the same phase. Frequency, on the other hand, refers to the number of cycles of a wave that occur in a given time period. Amplitude represents the maximum displacement of a wave from its equilibrium position. Wavelength is the distance between two consecutive points on a wave that are in phase. Therefore, the correct answer is 'Period' as it specifically refers to the time taken for a wave to complete one full cycle, distinguishing it from the other choices which represent different properties of a wave.

4. Which of the following statements is true regarding a supersaturated solution?

• A. It is unstable and tends to crystallize
• B. It contains more solute than it could dissolve
• C. It has a higher concentration than a saturated solution
• D. It is rarely encountered in everyday solutions

Correct answer: A

Rationale: A supersaturated solution is unstable and tends to crystallize because it contains more solute than it could dissolve at a given temperature. This excess solute is in a metastable state and can precipitate out if disturbed, leading to the formation of crystals. Option B is incorrect because a supersaturated solution does contain more solute than it could normally dissolve, but it becomes unstable due to this excess solute. Option C is incorrect because while a supersaturated solution does have a higher concentration than a saturated solution, the defining characteristic related to its instability is the excess solute. Option D is incorrect as supersaturated solutions can be encountered in various everyday scenarios, such as certain sugar solutions used in cooking or rock candy production.

5. Which of the following hormones would cause skin color to become darker?

• A. Follicle-stimulating
• B. Growth-stimulating
• C. Thyroid-stimulating
• D. Melanocyte-stimulating

Correct answer: D

Rationale: The correct answer is D, Melanocyte-stimulating. Melanocyte-stimulating hormone (MSH) stimulates melanocytes in the skin to produce more melanin, leading to darker skin pigmentation. Choices A, B, and C are incorrect as Follicle-stimulating hormone (FSH) stimulates follicle growth in the reproductive system, Growth-stimulating hormone is a vague term not specific to any known hormone, and Thyroid-stimulating hormone (TSH) stimulates the thyroid gland to produce thyroid hormones, not affecting skin color pigmentation.

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