Nursing Elites

1. Which of the following is a weak acid commonly found in citrus fruits?

• A. Sulfuric acid (Hâ‚‚SOâ‚„)
• B. Hydrochloric acid (HCl)
• C. Citric acid
• D. Nitric acid (HNO₃)

Correct answer: c

Rationale: Citric acid is a weak acid commonly found in citrus fruits. The other choices are strong acids.

2. A keystone species plays a critical role in an ecosystem because its removal would:

• A. Lead to a decrease in competition among other species
• B. Cause a slight increase in primary productivity
• C. Have a minimal impact on the overall ecosystem structure
• D. Disrupt the food web and cause cascading effects on other populations

Correct answer: D

Rationale: Rationale: Keystone species are species that have a disproportionately large effect on their environment relative to their abundance. They play a critical role in maintaining the structure and function of an ecosystem. If a keystone species is removed from an ecosystem, it can disrupt the food web by causing imbalances in predator-prey relationships. This disruption can lead to cascading effects on other populations within the ecosystem, potentially causing population declines or even extinctions. Therefore, the removal of a keystone species would have significant impacts on the overall ecosystem structure, making option D the correct answer.

3. Cartilage is a flexible connective tissue found in the:

• A. Center of long bones
• B. Joints between bones
• C. Muscle tissue
• D. Walls of blood vessels

Correct answer: A

Rationale: Cartilage is a flexible connective tissue that is found in the joints between bones. It is a strong yet flexible tissue that cushions and supports the joints, allowing for smooth movement and reducing friction between bones. Cartilage is not typically found in the center of long bones, muscle tissue, or walls of blood vessels. Therefore, the correct answer is B: 'Joints between bones.'

4. What is the main function of energy storage technologies in the context of renewable energy?

• A. Reduce the cost of producing solar and wind power.
• B. Enhance the efficiency of energy transmission and distribution.
• C. Compensate for the intermittent nature of renewable energy sources.
• D. Eliminate the need for fossil fuels in electricity generation.

Correct answer: C

Rationale: Choice C directly addresses the passage's emphasis on managing the fluctuating availability of renewable energy, hence being the main function of storage technologies.

5. Which element has the highest melting point of any element?

• A. Tungsten
• B. Iron
• C. Platinum
• D. Carbon

Correct answer: D

Rationale: Diamond's strong covalent bonds between carbon atoms make it incredibly resistant to heat and pressure, giving it the highest melting point.

6. What is the valve that prevents blood from flowing back from the left ventricle into the left atrium?

• A. Tricuspid valve
• B. Mitral valve
• C. Aortic valve
• D. Pulmonic valve

Correct answer: B

Rationale: The correct answer is B: Mitral valve. The mitral valve, also known as the bicuspid valve, is located between the left atrium and the left ventricle. Its primary function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The tricuspid valve is located between the right atrium and right ventricle, the aortic valve is located between the left ventricle and the aorta, and the pulmonic valve is located between the right ventricle and the pulmonary artery. Therefore, the mitral valve is specifically responsible for preventing backflow in the left side of the heart, making it the correct answer.

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