Nursing Elites

1. 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.

2. What phenomenon occurs when a wave encounters a change in medium causing a change in its speed and direction?

• A. Refraction
• B. Reflection
• C. Diffraction
• D. Interference

Correct answer: a

Rationale: Refraction happens when a wave changes its speed and direction due to encountering a change in medium.

3. What is the main function of the urinary system?

• A. Transporting oxygen
• B. Fighting off infections
• C. Maintaining acid-base balance
• D. All of the above

Correct answer: D

Rationale: The correct answer is D: 'All of the above.' The main function of the urinary system is not just limited to one specific task but encompasses multiple important functions. It is responsible for maintaining acid-base balance by regulating the pH of the blood through the excretion of acids and bases. Additionally, the urinary system plays a crucial role in filtering waste products from the blood and expelling them from the body, which helps in fighting off infections. Moreover, the urinary system is not involved in transporting oxygen, as this function is primarily carried out by the respiratory system. Therefore, 'All of the above' is the correct choice as it includes the comprehensive functions of the urinary system.

4. Which of the following is NOT a typical component of healthy semen?

• A. Sperm
• B. Fructose (sugar)
• C. Prostaglandins
• D. Urine

Correct answer: D

Rationale: The correct answer is D: Urine. Semen is a mixture of fluids from various glands in the male reproductive system. It typically contains sperm, fructose (sugar) to provide energy for the sperm, and prostaglandins to aid in sperm motility. Urine is not a normal component of healthy semen. It is important to note that urine and semen travel through different pathways in the male body, and they should not mix. Therefore, the presence of urine in semen would indicate a potential issue or infection in the urinary system. Understanding the components of healthy semen is crucial for assessing male reproductive health and fertility.

5. Which property of matter remains constant regardless of changes in gravity?

• A. Mass
• B. Weight
• C. Volume
• D. Density

Correct answer: A

Rationale: Mass is a measure of the amount of matter in an object and remains constant regardless of changes in gravity. Weight, on the other hand, is the force of gravity acting on an object's mass and can vary depending on the strength of gravity. Volume is the amount of space an object occupies, which can change depending on the environment, and density is the mass of an object per unit volume, which can also change with variations in gravity.

6. Aseptic meningitis is an inflammation of the meninges caused by:

• A. Bacteria
• B. Viruses
• C. Fungi
• D. Parasites

Correct answer: B

Rationale: Rationale: Aseptic meningitis is typically caused by viral infections, such as enteroviruses (e.g., coxsackievirus, echovirus), herpes simplex virus, varicella-zoster virus, and others. These viruses can infect the meninges, leading to inflammation and symptoms of meningitis without the presence of bacteria. While bacterial meningitis is a serious and life-threatening condition, aseptic meningitis caused by viruses is usually less severe and has a better prognosis. Fungi and parasites are less common causes of meningitis compared to bacteria and viruses.

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