Nursing Elites

1. What is the difference between a pure substance and a mixture?

• A. Pure substances have fixed composition, mixtures don't.
• B. Mixtures have fixed composition, pure substances don't
• C. Pure substances are always solids, mixtures can be any state
• D. Pure substances are always elements, mixtures are always compounds

Correct answer: A

Rationale: Rationale: - Pure substances have a definite and constant composition, meaning they are made up of only one type of atom or molecule. This composition does not vary. - Mixtures, on the other hand, are composed of two or more substances physically combined. The components of a mixture can be present in varying proportions, leading to a variable composition. - Option A correctly distinguishes between pure substances and mixtures based on the fixed composition of pure substances and the variable composition of mixtures.

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: 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. What is the involuntary muscle tissue found in the walls of blood vessels and organs like the stomach and intestines?

• A. Skeletal muscle
• B. Cardiac muscle
• C. Smooth muscle
• D. Striated muscle

Correct answer: C

Rationale: The correct answer is C: Smooth muscle. Smooth muscle is the involuntary muscle tissue that is found in the walls of blood vessels and organs like the stomach and intestines. Unlike skeletal muscle, which is voluntary and under conscious control, smooth muscle functions involuntarily, allowing organs to contract and relax without conscious effort. Cardiac muscle, while also involuntary, is specifically found in the heart. Striated muscle refers to both skeletal and cardiac muscle, which exhibit a striped appearance under a microscope due to the arrangement of their filaments. Therefore, smooth muscle is the most appropriate answer for this question.

4. What is the main function of the gallbladder?

• A. To store and concentrate bile
• B. To produce digestive enzymes
• C. To absorb nutrients
• D. To neutralize stomach acid

Correct answer: A

Rationale: Rationale: The gallbladder is a small organ located beneath the liver that plays a crucial role in the digestive system. Its main function is to store and concentrate bile, a digestive fluid produced by the liver. Bile is released from the gallbladder into the small intestine to help with the digestion and absorption of fats. The gallbladder acts as a reservoir for bile, allowing it to be released in a controlled manner when needed to aid in the digestion of fatty foods. Therefore, option A is the correct answer as it accurately describes the main function of the gallbladder.

5. What is the Doppler effect, and how does it explain the shift in frequency of sound waves perceived by an observer?

• A. It only affects light waves, not sound waves.
• B. It's the change in wave speed due to medium density.
• C. It's the perceived change in frequency due to relative motion.
• D. It's the bending of waves due to different mediums.

Correct answer: C

Rationale: The Doppler effect describes how the perceived frequency of a wave changes depending on the relative motion between the source and observer. For example, an approaching siren sounds higher pitched due to compressed wavefronts, while a receding siren sounds lower due to stretched wavefronts.

6. Which phrase best describes the tone of the passage?

• A. Humorous and lighthearted
• B. Suspenseful and mysterious
• C. Objective and informative
• D. Critical and judgmental

Correct answer: C

Rationale: The passage presents factual information without injecting personal opinions or emotions. A, B, and D suggest tones not present in the passage's neutral delivery.

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