Nursing Elites

1. Biodiversity is important for healthy ecosystems because it:

• A. Increases competition for resources
• B. Provides stability and resilience to disturbances
• C. Slows down nutrient cycling
• D. Reduces the number of decomposers

Correct answer: B

Rationale: Rationale: Biodiversity refers to the variety of living organisms in a particular area. A diverse ecosystem is better able to withstand and recover from disturbances such as natural disasters, climate change, or human impacts. This is because different species play unique roles in the ecosystem, and a higher level of biodiversity means there are more species available to fulfill these roles. For example, if one species is negatively affected by a disturbance, other species may be able to compensate for its loss, maintaining the overall functioning of the ecosystem. Therefore, biodiversity provides stability and resilience to disturbances, making ecosystems healthier and more sustainable.

2. Which of the following numbers is the greatest common factor (GCF) of 12 and 18?

• A. 2
• B. 3
• C. 6
• D. 9

Correct answer: C

Rationale: The GCF is the largest number that is a factor of both 12 and 18. We can factor each number to find common factors: 12 = 2 x 2 x 3 and 18 = 2 x 3 x 3. The greatest common factor that appears in both factorizations is 6 (2 x 3).

3. During exercise, heart rate increases to deliver more oxygen to the body's tissues. What other cardiovascular response also increases?

• A. Blood pressure decreases
• B. Blood vessel diameter narrows
• C. Blood flow to muscles increases
• D. Blood viscosity thickens

Correct answer: A

Rationale: The correct answer is A: 'Blood pressure decreases.' When the heart rate increases during exercise to deliver more oxygen to the body's tissues, the blood pressure also tends to decrease. This is due to the enhanced efficiency of the heart in pumping blood, resulting in a lower pressure exerted on the blood vessel walls. In contrast, options B and D are incorrect as blood vessel diameter typically widens (dilates) during exercise to facilitate increased blood flow, and blood viscosity does not usually thicken during exercise. Option C is a distractor as blood flow to muscles indeed increases during exercise to meet the higher demand for oxygen and nutrients.

4. Which term refers to the resistance of a liquid to flow?

• A. Density
• B. Viscosity
• C. Surface tension
• D. Boiling point

Correct answer: B

Rationale: Viscosity is the term that refers to the resistance of a liquid to flow. It is a measure of how thick or sticky a fluid is, and it determines how easily a liquid can flow. Density (A) is a measure of how much mass is contained in a given volume, surface tension (C) is the property of a liquid that allows it to resist an external force due to the cohesive nature of its molecules, and boiling point (D) is the temperature at which a liquid changes to a vapor.

5. Cherenkov radiation is a characteristic phenomenon associated with:

• A. Alpha particle emission
• B. Beta particle emission
• C. Gamma ray emission
• D. Charged particles exceeding the speed of light in a medium

Correct answer: C

Rationale: Cherenkov radiation is a phenomenon associated with charged particles exceeding the speed of light in a medium. When a charged particle travels faster than the speed of light in that medium, it emits a characteristic blue glow known as Cherenkov radiation. This occurs due to the disruption of the electromagnetic field in the medium by the high-speed particle. Options A, B, and C are not correct as they do not directly relate to the specific condition required for Cherenkov radiation to be produced. Therefore, option D, 'Charged particles exceeding the speed of light in a medium,' is the correct answer.

6. After exposure to a pathogen, the immune system develops memory. What type of immune cell is responsible for this immunological memory?

• A. B cells
• B. T cells (specifically memory T cells)
• C. Phagocytes
• D. Natural killer cells

Correct answer: B

Rationale: The correct answer is A: "B cells." B cells are responsible for generating immunological memory after exposure to a pathogen. When B cells encounter a pathogen, they differentiate into memory B cells, which can quickly recognize and respond to the pathogen upon subsequent exposure. These memory B cells are crucial for mounting a faster and more effective immune response, leading to a quicker clearance of the pathogen. T cells, phagocytes, and natural killer cells play important roles in the immune response, but specifically, memory B cells are responsible for immunological memory.

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