Nursing Elites

1. What is the independent variable in this experiment?

• A. Time
• B. Dog weight
• C. Dog species
• D. Dog food type

Correct answer: D

Rationale: The independent variable is the factor that is manipulated by the researcher to observe its effects on the dependent variable. In this experiment, the researcher is likely changing the type of dog food, and this manipulation is what impacts the outcome being measured. Therefore, 'Dog food type' is the independent variable. Choices A, B, and C do not represent the variable being intentionally changed by the researcher, making them dependent variables or other factors not directly controlled or manipulated in this experiment.

2. What are organisms that break down dead organisms and return nutrients to the environment called?

• A. Producers
• B. Decomposers
• C. Consumers
• D. Parasites

Correct answer: B

Rationale: Decomposers are essential organisms in the ecosystem as they break down dead organisms and organic matter, such as bacteria, fungi, and some insects. By decomposing complex organic materials into simpler forms, they release nutrients back into the environment for other organisms to utilize. Producers (option A) are organisms that generate their own food through photosynthesis; consumers (option C) are organisms that feed on other organisms for energy, and parasites (option D) are organisms that live on or in another organism, benefiting at the host's expense rather than breaking down dead organisms for nutrient recycling.

3. What happens to the frequency of a wave if its wavelength decreases while the speed remains constant?

• A. Frequency decreases
• B. Frequency increases
• C. Frequency remains constant
• D. Frequency becomes zero

Correct answer: B

Rationale: The correct answer is B: Frequency increases. Frequency and wavelength are inversely proportional in a wave with a constant speed. When the wavelength decreases while the speed remains constant, the frequency must increase to maintain the constant speed of the wave. This relationship is governed by the equation: speed = frequency x wavelength. Choice A is incorrect as frequency increases when wavelength decreases. Choice C is incorrect as the frequency changes in this scenario. Choice D is incorrect as the frequency does not become zero but increases when the wavelength decreases.

4. What is the primary function of B cells in the immune system?

• A. Directly attacking and engulfing pathogens
• B. Producing antibodies specific to a pathogen
• C. Destroying infected body cells
• D. All of the above

Correct answer: B

Rationale: B cells are a type of white blood cell that primarily functions by producing antibodies specific to a pathogen. These antibodies play a crucial role in marking pathogens for destruction by other immune cells. While B cells are essential for the immune response, they do not directly attack and engulf pathogens or destroy infected body cells. These functions are carried out by other immune cells like macrophages and cytotoxic T cells. Therefore, the correct answer is B, as it accurately reflects the primary role of B cells in the immune system.

5. What is the main function of valence electrons in chemical bonding?

• A. They are responsible for holding the nucleus together.
• B. They are involved in forming bonds with other atoms.
• C. They determine the element's physical properties.
• D. They play no role in chemical reactions.

Correct answer: B

Rationale: Valence electrons are the electrons in the outermost energy level of an atom. These electrons are involved in forming bonds with other atoms, which is crucial for chemical bonding. By participating in bonding, valence electrons determine an atom's ability to form compounds and engage in chemical reactions. Therefore, the primary function of valence electrons is to facilitate the formation of bonds between atoms, making option B the correct answer. Choices A, C, and D are incorrect because valence electrons primarily influence chemical bonding by participating in the formation of bonds between atoms, rather than holding the nucleus together, determining physical properties, or having no role in chemical reactions.

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