Nursing Elites

1. If Silicon (Si) has an atomic mass of 28.1 AMU (atomic mass units), which of the following is the most likely number of neutrons an atom of Silicon would have?

• A. 28.1
• B. 14
• C. 28
• D. 14.2

Correct answer: B

Rationale: Silicon has an atomic number of 14, indicating it has 14 protons. The atomic mass of 28.1 AMU accounts for both protons and neutrons in the nucleus. By subtracting the atomic number from the atomic mass, we can estimate the number of neutrons in the atom. Thus, 28.1 - 14 = 14 neutrons. Choice A is incorrect as it represents the total atomic mass, not the number of neutrons. Choice C is incorrect; it is the atomic number (protons) rather than the number of neutrons. Choice D is incorrect as it is a value that does not reflect the number of neutrons in the silicon atom.

2. Decomposers in an ecosystem play a vital role by:

• A. Photosynthesizing and producing organic matter
• B. Breaking down dead organisms and returning nutrients to the environment
• C. Preying on herbivores and controlling their populations
• D. Fixing nitrogen from the atmosphere and making it available to plants

Correct answer: B

Rationale: Decomposers are organisms that break down dead organic matter, such as dead plants and animals, into simpler substances. By doing so, they help to recycle nutrients back into the environment, making them available for other organisms to use. This process is essential for the functioning of ecosystems, as it ensures that nutrients are not lost but instead are continuously cycled through the ecosystem. Photosynthesis (option A) is the process by which plants and some other organisms convert light energy into chemical energy in the form of glucose, and it is not a role of decomposers. Preying on herbivores (option C) is a role typically carried out by predators, not decomposers. Fixing nitrogen from the atmosphere (option D) is a process carried out by nitrogen-fixing bacteria, not decomposers.

3. Which neuromuscular system controls voluntary movement?

• A. Autonomic
• B. Somatic
• C. Sympathetic
• D. Parasympathetic

Correct answer: B

Rationale: The correct answer is B, Somatic. The somatic nervous system controls voluntary movements of skeletal muscles. It is responsible for carrying sensory and motor information to and from the central nervous system. Choices A, C, and D are incorrect. The autonomic nervous system (choice A) controls involuntary functions such as heart rate and digestion. The sympathetic (choice C) and parasympathetic (choice D) nervous systems are subdivisions of the autonomic nervous system and are responsible for the body's fight-or-flight response and rest-and-digest functions, respectively.

4. What is the main purpose of biological classification?

• A. To create a rigid and unchanging system for labeling organisms
• B. To understand the diversity and interconnectedness of life
• C. To simplify nature into neat and tidy categories
• D. To assign organisms to specific ecological niches

Correct answer: B

Rationale: Biological classification, also known as taxonomy, is the science of categorizing and organizing living organisms based on shared characteristics. The main purpose of biological classification is not to create a rigid and unchanging system (option A) or to simplify nature into neat and tidy categories (option C). Instead, it aims to help us understand the diversity of life on Earth and how different organisms are related to each other. By classifying organisms into groups based on their evolutionary relationships, we can gain insights into the interconnectedness of life and better appreciate the complexity and beauty of the natural world. Assigning organisms to specific ecological niches (option D) is more related to ecological studies rather than biological classification.

5. Which of the following is a strong base commonly used in cleaning products?

• A. Sodium hydroxide (NaOH)
• B. Ammonium hydroxide (NH₄OH)
• C. Calcium hydroxide (Ca(OH)₂)
• D. Potassium hydroxide (KOH)

Correct answer: A

Rationale: Sodium hydroxide (NaOH) is a strong base commonly used in cleaning products due to its effectiveness in breaking down grease and fats. It is known for its corrosive properties and is commonly found in drain cleaners and oven cleaners. While ammonium hydroxide, calcium hydroxide, and potassium hydroxide are also bases, they are not as strong as sodium hydroxide and are not as commonly used in cleaning products. Ammonium hydroxide is more commonly found in household cleaning products for its disinfectant properties, calcium hydroxide is used in agriculture and construction, and potassium hydroxide is often used in industries like soap manufacturing and biodiesel production.

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