Nursing Elites

1. Homologous structures are similar structures in different organisms that have a common evolutionary origin. An example is:

• A. Butterfly wings and bird wings (analogous structures with different origins)
• B. The arm of a human, the wing of a bat, and the flipper of a whale
• C. The eyes of an octopus and a human (convergent evolution with different origins)
• D. The stinger of a bee and the barb of a cactus (unrelated structures)

Correct answer: B

Rationale: Homologous structures are similar structures found in different organisms that share a common evolutionary origin. The arm of a human, the wing of a bat, and the flipper of a whale are all examples of homologous structures. Despite serving different functions, they share a common underlying structure due to their evolutionary relationship, evidencing a shared ancestry. These structures are modified over time to suit the specific needs of each species. Option A (Butterfly wings and bird wings) refers to analogous structures with different origins. Option C (The eyes of an octopus and a human) describes convergent evolution where traits evolve independently. Option D (The stinger of a bee and the barb of a cactus) are unrelated structures.

2. A symbiotic relationship where one organism benefits and the other is not harmed is called:

• A. Mutualism
• B. Commensalism
• C. Parasitism
• D. Predation

Correct answer: B

Rationale: B) Commensalism: In commensalism, one organism benefits while the other is neither helped nor harmed. This is the relationship described in the question. The correct answer is Commensalism because it specifically fits the scenario where one organism benefits without affecting the other. A) Mutualism: In mutualism, both organisms involved benefit from the relationship. C) Parasitism: In parasitism, one organism benefits at the expense of the other organism, which is harmed. D) Predation: In predation, one organism (predator) kills and consumes another organism (prey) for food.

3. The pH scale is used to indicate the concentration of:

• A. Hydrogen ions
• B. Oxygen
• C. Salts
• D. Sugar molecules

Correct answer: A

Rationale: The pH scale is a measure of the concentration of hydrogen ions in a solution, representing its acidity or basicity. A lower pH value indicates higher hydrogen ion concentration and acidity, while a higher pH value indicates lower hydrogen ion concentration and basicity. Choice A, 'Hydrogen ions,' is the correct answer because the pH scale specifically measures the concentration of hydrogen ions in a solution. Choices B, C, and D are incorrect as the pH scale is not used to indicate the concentration of oxygen, salts, or sugar molecules.

4. Which type of reaction is represented by the equation A + B → AB?

• A. Synthesis
• B. Decomposition
• C. Single Replacement
• D. Double Replacement

Correct answer: A

Rationale: The correct answer is 'Synthesis.' In a synthesis reaction, two or more reactants combine to form a single product. The equation A + B → AB represents a synthesis reaction where substances A and B combine to form compound AB. Choice B, 'Decomposition,' involves a single compound breaking down into two or more simpler substances, which is not the case in this equation. Choices C and D, 'Single Replacement' and 'Double Replacement,' involve the replacement of elements in compounds or the exchange of ions between compounds, neither of which is depicted in the given equation. Thus, 'Synthesis' is the most suitable classification for the reaction A + B → AB.

5. Which of the following systems is responsible for transporting blood throughout the body?

• A. Respiratory
• B. Circulatory
• C. Nervous
• D. Digestive

Correct answer: B

Rationale: The correct answer is B: Circulatory. The circulatory system, made up of the heart, blood vessels, and blood, is responsible for transporting blood throughout the body. It plays a vital role in delivering oxygen, nutrients, hormones, and removing waste products from cells. The respiratory system, on the other hand, is responsible for gas exchange in the lungs. The nervous system transmits signals between different parts of the body, while the digestive system processes food and absorbs nutrients from it. Therefore, choices A, C, and D are incorrect as they are not primarily involved in the transportation of blood throughout the body.

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