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 like lemons, oranges, and limes. It is responsible for the sour taste in these fruits. Sulfuric acid (option A), hydrochloric acid (option B), and nitric acid (option D) are all strong acids that are typically used in laboratory settings and industrial processes, not naturally found in citrus fruits. Therefore, the correct answer is option C.

2. Which of the following is an example of a tissue?

• A. chloroplasts
• B. liver
• C. mammal
• D. hamstring

Correct answer: B

Rationale: The correct answer is 'B: liver.' The liver is an example of a tissue. Tissues are groups of cells that work together to perform specific functions in the body. The liver is made up of different types of cells that work together to carry out various essential functions, such as detoxification, metabolism, and storage of nutrients. Option A (chloroplasts) refers to organelles, not tissues. Option D (hamstring) is a muscle, not a tissue. Option C (mammal) represents a higher level of organization than tissues, as it refers to a classification of organisms, not a specific tissue type.

3. When two cars with different masses collide head-on, which car experiences a greater change in momentum?

• A. The car with the larger mass
• B. The car with the smaller mass
• C. Both cars experience the same change in momentum
• D. It depends on the initial velocities of the cars

Correct answer: C

Rationale: In a head-on collision between two cars, the law of conservation of momentum states that the total momentum of the isolated system remains constant before and after the collision. The change in momentum of one car is equal in magnitude but opposite in direction to the change in momentum of the other car. As a result, both cars experience the same change in momentum during the collision. Choice A is incorrect because the change in momentum is the same for both cars due to the conservation of momentum principle. Choice B is incorrect as the smaller mass car does not experience a greater change in momentum. Choice D is incorrect as the initial velocities of the cars do not determine which car experiences a greater change in momentum; it is solely dependent on the masses of the colliding cars.

4. What structure in plant cells provides rigidity and support?

• A. Cell membrane
• B. Golgi apparatus
• C. Plastid
• D. Cell wall

Correct answer: D

Rationale: The correct answer is D, the cell wall. The cell wall is the structure in plant cells that provides rigidity and support. It is a tough, rigid structure located outside the cell membrane. Composed primarily of cellulose, the cell wall offers structural support to the cell, helping it maintain its shape and protect it from damage. The other choices, such as the cell membrane (choice A), Golgi apparatus (choice B), and plastid (choice C) do not provide rigidity and support to plant cells. The cell membrane is a selectively permeable barrier, the Golgi apparatus is involved in processing and packaging proteins, and plastids are organelles responsible for functions like photosynthesis and storage, but they do not provide the structural support that the cell wall does.

5. When animals eat, insulin is released from the pancreas, stimulating glucose uptake by the liver. When glucose levels drop, the pancreas reduces insulin release. This is an example of which mechanism for maintaining homeostasis?

• A. Negative feedback.
• B. Positive feedback.
• C. Stress response.
• D. Parasympathetic regulation.

Correct answer: A

Rationale: This mechanism is an example of negative feedback. Negative feedback systems work to counteract changes in the body and maintain a stable internal environment (homeostasis). In this case, the release of insulin in response to high glucose levels is followed by a reduction in insulin release when glucose levels drop. This response helps regulate glucose levels and return them to a normal range, demonstrating the characteristic of negative feedback where the body's response opposes the initial stimulus to maintain equilibrium. Positive feedback would amplify the initial change rather than counteract it, so it is not the correct choice. Stress response and parasympathetic regulation are not directly involved in this glucose regulation process, making them incorrect choices.

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