Nursing Elites

1. During a scientific investigation, what is intentionally changed or manipulated?

• A. The dependent variable.
• B. The control.
• C. The hypothesis.
• D. The independent variable.

Correct answer: D

Rationale: During a scientific investigation, the independent variable is intentionally changed or manipulated by the researcher to observe its impact or effect on the dependent variable. The independent variable is the one being tested or studied to see how it influences the dependent variable. In contrast, the dependent variable is the outcome or response that is measured in an experiment and is expected to change as a result of the manipulation of the independent variable. Choices A, B, and C are not directly altered during a scientific investigation but play different roles in the research process. Therefore, the correct answer is D - the independent variable.

2. Which of the following is an example of stabilizing selection?

• A. Selection that favors extreme traits in a population
• B. Selection that removes individuals with extreme traits
• C. Selection that maintains the current average trait in a population
• D. Selection that favors one specific trait over all others

Correct answer: C

Rationale: - Stabilizing selection is a type of natural selection that favors the intermediate variants in a population, while selecting against the extreme traits. This results in the maintenance of the current average trait in the population. - Option A is incorrect because stabilizing selection does not favor extreme traits; instead, it favors the average trait. - Option B is incorrect because stabilizing selection does not remove individuals with extreme traits; it acts against extreme traits by favoring the intermediate variants. - Option D is incorrect because stabilizing selection does not favor one specific trait over all others; it favors the average trait by selecting against extreme traits.

3. Which part of the cell serves as the control center for all cell activity?

• A. Nucleus
• B. Cell membrane
• C. Cytoplasm
• D. Mitochondria

Correct answer: A

Rationale: The corrected question and answer are accurate. The correct answer is A: Nucleus. The nucleus is known as the control center of the cell as it contains the cell's genetic material (DNA) and directs all cell activities including growth, metabolism, and reproduction. The other organelles listed in the choices, while important for various cellular functions, do not serve as the central control center for overall cell activity.

4. In aerobic respiration, how many ATP molecules are produced per molecule of FADH2?

• A. 1
• B. 2
• C. 3
• D. 4

Correct answer: B

Rationale: The correct answer is B: 2. During aerobic respiration, each molecule of FADH2 produces 2 ATP molecules. FADH2 enters the electron transport chain and contributes to the generation of ATP. Choice A (1), Choice C (3), and Choice D (4) are incorrect because FADH2 specifically yields 2 ATP molecules per molecule in the process of aerobic respiration.

5. Which organ system is most responsible for maintaining control of body temperature?

• A. The skeletal system.
• B. The circulatory system.
• C. The immune system.
• D. The muscular system.

Correct answer: B

Rationale: The circulatory system is the correct answer as it plays a crucial role in maintaining control of body temperature through a process called thermoregulation. Blood vessels near the skin surface dilate to dissipate heat when the body is too warm and constrict to reduce heat loss when it's too cold. Additionally, the circulatory system helps distribute heat produced from metabolic processes throughout the body to keep a stable internal temperature. The skeletal system provides structural support, the immune system defends against pathogens, and the muscular system is responsible for movement, but they are not primarily involved in regulating body temperature.

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