Nursing Elites

1. Which valve prevents backflow into the atrium when the ventricles contract?

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

Correct answer: B

Rationale: The tricuspid valve (right atrioventricular valve) prevents backflow into the right atrium when the right ventricle contracts. This valve ensures that blood flows in the correct direction, preventing regurgitation into the atrium. The pulmonary valve is responsible for preventing backflow into the right ventricle from the pulmonary artery. The mitral valve prevents backflow into the left atrium, and the aortic valve prevents backflow into the left ventricle from the aorta. Therefore, the correct answer is the tricuspid valve as it specifically addresses the scenario of backflow into the atrium during ventricular contraction.

2. When is work done by a force on an object?

• A. Only when the object moves in the direction of the force
• B. Only when the object moves against the force
• C. Only when the object moves vertically
• D. Only when the force is applied for a specific duration

Correct answer: A

Rationale: Work is done by a force on an object when the object moves in the direction of the force. This is because work is defined as the product of the force applied to an object and the distance over which the force is applied. When the object moves in the direction of the force, the force contributes to the displacement of the object, resulting in work being done. If the object moves perpendicular to the force, no work is done because the force does not contribute to the displacement. Moving against the force also results in work being done as the force is causing the displacement. The vertical movement of the object does not determine whether work is done; it is the alignment of the force with the object's displacement that matters. The duration of force application does not impact whether work is done; as long as the force causes the object to move in its direction, work is being done.

3. What is the temperature of 35°C in Kelvin?

• A. 220
• B. 238
• C. 308
• D. 345

Correct answer: C

Rationale: To convert Celsius to Kelvin, add 273.15 to the Celsius temperature. In this case, 35°C + 273.15 = 308.15 K. Therefore, the correct answer is 308 K. Choice A (220) is incorrect as it does not account for adding 273.15 to convert to Kelvin. Choice B (238) is incorrect as it is not the result of adding 273.15 to 35°C. Choice D (345) is incorrect as it is not the correct conversion of 35°C to Kelvin.

4. Which of these pairs represents an example of convergent evolution?

• A. Humans and chimpanzees
• B. Bats and birds
• C. Dolphins and sharks
• D. Snakes and earthworms

Correct answer: B

Rationale: Convergent evolution refers to the process by which different species independently evolve similar traits or characteristics due to similar environmental pressures. In the case of bats and birds, both have evolved wings for flight despite not sharing a recent common ancestor with wings. Bats are mammals, while birds are avians, yet they both have wings adapted for flight, which is a classic example of convergent evolution. A) Humans and chimpanzees share a common ancestor and have not independently evolved similar traits. C) Dolphins and sharks are not closely related, and their similarities are due to adaptations to their aquatic environment rather than convergent evolution. D) Snakes and earthworms belong to different classes (reptiles and annelids, respectively) and do not share recent common ancestors, making their similarities not a result of convergent evolution.

5. Which of the following is responsible for producing antibodies?

• A. Red blood cells
• B. White blood cells
• C. Platelets
• D. Plasma

Correct answer: B

Rationale: White blood cells are responsible for producing antibodies. Antibodies are essential components of the immune system that help the body combat infections by identifying and neutralizing harmful pathogens. Red blood cells are primarily responsible for carrying oxygen, platelets are involved in blood clotting, and plasma is the liquid component of blood that carries nutrients and hormones.

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