Nursing Elites

1. What property of matter remains constant regardless of changes in gravity?

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

Correct answer: a

Rationale: Mass is the measure of the amount of matter in an object and remains constant regardless of changes in gravity or location. It is an intrinsic property of matter.

2. When a car brakes to a stop, friction between the tires and the road acts as:

• A. A balanced force
• B. An unbalanced force causing acceleration
• C. An unbalanced force causing the car to remain at rest
• D. No force at all

Correct answer: B

Rationale: Friction opposes the car's motion, acting as an unbalanced force that decelerates the car and brings it to a stop.

3. Negative feedback mechanisms are crucial in the endocrine system to:

• A. Increase hormone production continuously
• B. Maintain hormone levels within a specific range
• C. Cause a constant release of hormones
• D. Disrupt communication between glands

Correct answer: B

Rationale: The correct answer is B: 'Maintain hormone levels within a specific range.' Negative feedback mechanisms in the endocrine system are essential for regulating hormone levels. These mechanisms work to counteract any deviations from the set point, ensuring that hormone levels remain balanced and within the optimal range for proper physiological function. Continuous hormone production (A) or constant release of hormones (C) would lead to imbalances and potential harm to the body. Disrupting communication between glands (D) would hinder the coordination necessary for maintaining homeostasis. Therefore, option B is the best choice as it highlights the critical role of negative feedback in keeping hormone levels stable and regulated.

4. What is the net ionic equation for the reaction: 2HCl(aq) + Ba(OH)2(aq) → 2H2O(l) + BaCl2(aq)?

• A. 2H+(aq) + 2OH-(aq) → 2H2O(l)
• B. 2HCl(aq) + Ba(OH)2(aq) → BaCl2(aq) + 2H2O(l)
• C. 2H+(aq) + Ba2+(aq) → Ba2+(aq) + 2H+(aq)
• D. Ba(OH)2(aq) + HCl(aq) → BaCl2(aq) + 2H2O(l)

Correct answer: a

Rationale: The net ionic equation includes only the species that undergo a change during the reaction.

5. Which part of the brainstem is responsible for controlling vital functions such as heart rate, blood pressure, and breathing?

• A. Medulla oblongata
• B. Pons
• C. Midbrain
• D. Cerebellum

Correct answer: a

Rationale: The correct answer is A: Medulla oblongata. The medulla oblongata is the lower part of the brainstem that regulates vital autonomic functions such as heart rate, blood pressure, and breathing. It contains important centers for controlling these essential bodily functions, making it a critical part of the brain for maintaining life. The pons, midbrain, and cerebellum are also parts of the brainstem, but they are not primarily responsible for regulating these vital functions. Therefore, the medulla oblongata is the specific region of the brainstem that directly controls these essential physiological processes.

6. Fingernails and toenails are made primarily of:

• A. Collagen (Collagen is found in the dermis)
• B. Keratin
• C. Melanin (Melanin provides pigment, not structure)
• D. Sebum (Sebum is an oily substance)

Correct answer: B

Rationale: The correct answer is B: Keratin. Fingernails and toenails are primarily made of a tough protein called keratin. Keratin is a fibrous structural protein that also makes up hair and the outer layer of skin. Collagen, as mentioned in option A, is found in the dermis of the skin and is responsible for providing strength and elasticity to the skin. Melanin, as in option C, is a pigment that gives color to the skin, hair, and eyes, but it does not contribute to the structure of nails. Sebum, as in option D, is an oily substance produced by the sebaceous glands in the skin to moisturize and protect the skin, but it is not a component of nails.

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