Nursing Elites

1. Why is biodiversity important for healthy ecosystems?

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

Correct answer: B

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. Choice A is incorrect because biodiversity doesn't increase competition for resources but rather helps in maintaining a balance within the ecosystem. Choice C is incorrect as biodiversity does not slow down nutrient cycling; in fact, it enhances nutrient cycling by ensuring a variety of species involved in the process. Choice D is incorrect as biodiversity does not reduce the number of decomposers but instead supports a diverse community of decomposers that are essential for nutrient recycling in ecosystems.

2. Which hormone, produced by the pancreas, is involved in the regulation of blood sugar levels by inhibiting the release of insulin and promoting the release of glucose into the bloodstream?

• A. Insulin
• B. Glucagon
• C. Cortisol
• D. Somatostatin

Correct answer: D

Rationale: The correct answer is D, Somatostatin. Somatostatin is a hormone produced by the pancreas that plays a crucial role in regulating blood sugar levels by inhibiting the release of insulin and promoting the release of glucose into the bloodstream. It acts as a counterbalance to insulin, preventing excess insulin secretion and ensuring the availability of glucose when needed. Therefore, somatostatin helps maintain blood sugar balance in the body. Choices A, B, and C are incorrect. Insulin is responsible for lowering blood sugar levels, while glucagon and cortisol have roles that differ from the functions described in the question.

3. 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.

4. How are mass and inertia related?

• A. Mass is a measure of inertia
• B. Mass has no relationship with inertia
• C. Inertia is a measure of weight
• D. Inertia increases with decreasing mass

Correct answer: A

Rationale: Mass is a measure of inertia. Inertia is the resistance of an object to changes in its state of motion, and mass quantifies this resistance. Objects with more mass have greater inertia, meaning they are more resistant to changes in their motion. Therefore, mass and inertia are directly related, with mass being a fundamental factor that determines the level of inertia an object possesses. Choice B is incorrect because mass and inertia are indeed related. Choice C is incorrect as inertia is not a measure of weight but rather a property related to an object's mass. Choice D is incorrect because inertia actually increases with increasing mass, not decreasing mass.

5. An investigator wishes to test the effect of temperature on the durability of a certain material. He places five blocks of this material in a sunny area in a meadow and five more in a cold area high in the mountains. He then monitors them over time. What is the main problem with this experiment?

• A. Ten subjects are far too small a number to obtain effective results.
• B. It is impossible to control for the fact that the blocks in the mountains were placed later.
• C. There are too many variables that are not being controlled for.
• D. Nothing is wrong with this experiment; this demonstrates good experimental procedure.

Correct answer: C

Rationale: The main problem with this experiment is that there are too many variables that are not being controlled for. The investigator is only changing one variable (temperature) while there are other variables at play such as humidity, exposure to light, and potential differences in the material itself. Without controlling or accounting for these additional variables, it would be difficult to determine if any observed differences in durability are solely due to temperature. Choice A is incorrect because the issue is not solely about the number of subjects but about the lack of control over variables. Choice B is not the main problem as the order of placement may not significantly impact the results. Choice D is incorrect as the experiment lacks proper control over variables, which is a crucial aspect of good experimental procedure.

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