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. Which hormone, produced by the pancreas, acts in opposition to insulin by increasing blood sugar levels?

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

Correct answer: b

Rationale: The correct answer is B: Glucagon. Glucagon is a hormone produced by the pancreas that acts in opposition to insulin. When blood sugar levels are low, glucagon stimulates the liver to convert stored glycogen into glucose, which raises blood sugar levels. Insulin, on the other hand, lowers blood sugar levels by promoting the uptake and storage of glucose. Cortisol, produced by the adrenal glands, plays a role in stress response and metabolism but does not directly regulate blood sugar levels. Thyroxine, produced by the thyroid gland, regulates metabolism but does not directly affect blood sugar levels. Therefore, glucagon is the hormone that acts in opposition to insulin by increasing blood sugar levels.

3. What is the process by which muscles convert chemical energy (ATP) into mechanical energy (movement)?

• A. Photosynthesis
• B. Cellular respiration
• C. Muscle contraction
• D. The sliding filament theory

Correct answer: D

Rationale: The correct answer is D, the sliding filament theory. This theory explains how muscle contraction occurs at a molecular level. During muscle contraction, actin and myosin filaments slide past each other, causing the muscle to shorten and generate movement. This process requires the conversion of chemical energy stored in ATP into mechanical energy to power muscle contractions. Options A and B, photosynthesis and cellular respiration, involve energy production in plants and cells but are not directly related to muscle movement. Option C, muscle contraction, is a broad term that encompasses the entire process of muscle movement, while option D specifically addresses the molecular mechanism behind muscle contraction.

4. What is the momentum of a car with a mass of 1500 kg moving at a speed of 20 m/s?

• A. 30,000 kg m/s
• B. 1500 kg m/s
• C. 20 kg m/s
• D. Momentum cannot be determined without knowing the direction of motion.

Correct answer: A

Rationale: Momentum is defined as the product of mass and velocity. Momentum = mass x velocity = 1500 kg x 20 m/s = 30,000 kg m/s.

5. Nuclear fusion powers the sun and other stars. What is the main obstacle to achieving controlled nuclear fusion on Earth for energy production?

• A. Lack of suitable materials to handle high temperatures and pressures.
• B. Limited availability of fusion fuels like deuterium and tritium.
• C. Difficulty in containing the plasma where fusion occurs.
• D. All of the above.

Correct answer: D

Rationale: The main obstacle to achieving controlled nuclear fusion on Earth for energy production involves a combination of factors. A) Lack of suitable materials to handle high temperatures and pressures is a significant challenge due to the extreme conditions required for fusion reactions. B) Limited availability of fusion fuels like deuterium and tritium can pose a constraint on the scalability and sustainability of fusion energy. C) Difficulty in containing the plasma where fusion occurs is another critical issue as plasma instabilities and heat losses can hinder the efficiency of fusion reactions. Therefore, all of the options (A, B, and C) contribute to the challenges in achieving controlled nuclear fusion for energy production on Earth.

6. The dome-shaped muscular structure that separates the chest cavity from the abdominal cavity is the:

• A. Diaphragm
• B. Sternum
• C. Pericardium
• D. Trachea

Correct answer: A

Rationale: The correct answer is A: Diaphragm. The diaphragm is a dome-shaped muscular structure that plays a crucial role in respiration by contracting and flattening during inhalation to increase the volume of the thoracic cavity, allowing the lungs to expand and fill with air. It separates the chest cavity (thoracic cavity) from the abdominal cavity. The sternum (B) is a flat bone in the center of the chest, the pericardium (C) is a double-layered sac that surrounds the heart, and the trachea (D) is the windpipe that connects the larynx to the bronchi. Therefore, the diaphragm is the correct answer in this case.

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