Nursing Elites

1. Autoimmune diseases occur when the immune system mistakenly attacks healthy body tissues. What is a potential cause of autoimmune diseases?

• A. Deficiency in essential vitamins and minerals
• B. Exposure to environmental toxins
• C. Breakdown in immune cell self-tolerance mechanisms
• D. All of the above

Correct answer: C

Rationale: Autoimmune diseases result from a breakdown in immune cell self-tolerance mechanisms, leading to the immune system mistakenly attacking healthy body tissues. While deficiencies in essential vitamins and minerals or exposure to environmental toxins can impact overall health, they are not direct causes of autoimmune diseases. Deficiency in essential vitamins and minerals may weaken the immune system, making it more susceptible to various health issues but does not directly cause autoimmune diseases. Exposure to environmental toxins can trigger immune responses, but autoimmune diseases specifically stem from the breakdown of self-tolerance mechanisms within immune cells. Therefore, the correct answer is a breakdown in immune cell self-tolerance mechanisms.

2. What impact would the removal of a keystone species have in an ecosystem?

• 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: Keystone species play a crucial role in maintaining the balance and structure of an ecosystem due to their significant influence. If a keystone species is removed, it disrupts the delicate food web dynamics and can trigger cascading effects throughout the ecosystem. The disruption in predator-prey relationships can lead to population declines and even extinctions of other species. Options A, B, and C are incorrect because the removal of a keystone species would not decrease competition among other species, cause a slight increase in primary productivity, or have a minimal impact on the overall ecosystem structure. Instead, it would have a profound impact, disrupting the food web and causing cascading effects on other populations.

3. Which of the following bones is part of the axial skeleton?

• A. Femur
• B. Humerus
• C. Skull
• D. Pelvis

Correct answer: C

Rationale: The correct answer is C: Skull. The axial skeleton consists of bones along the body's central axis, including the skull, vertebral column, ribs, and sternum. Choices A, B, and D are incorrect because the femur, humerus, and pelvis are part of the appendicular skeleton, which comprises the bones of the limbs and girdles.

4. Which term refers to a position toward the feet? For example, the foot is part of the inferior extremity.

• A. Anterior
• B. Posterior
• C. Superior
• D. Inferior

Correct answer: D

Rationale: The correct answer is 'Inferior.' 'Inferior' refers to a position located towards the feet or lower part of the body. This is the opposite of 'superior,' which indicates a position towards the head or upper part of the body. 'Anterior' refers to the front of the body, 'posterior' refers to the back of the body, making them incorrect choices in this context.

5. What would be an appropriate control variable for this experiment?

• A. The period
• B. The length of the string
• C. The mass of the ball
• D. The color of the ball

Correct answer: C

Rationale: The mass of the ball would be an appropriate control variable for this experiment. By keeping the mass constant, you can ensure that any observed effects are not due to variations in mass but rather to the manipulated independent variable. Controlling the mass helps isolate and identify the true impact of the independent variable being studied. Choices A, B, and D are incorrect. The period and length of the string are more likely to be independent variables or factors being manipulated in the experiment. The color of the ball is considered an extraneous variable that is not typically controlled for in this type of experiment.

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