Nursing Elites

1. Which of the following is an example of a polymer?

• A. Methane
• B. Ethanol
• C. Polyethylene
• D. Acetic acid

Correct answer: C

Rationale: The correct answer is C, Polyethylene. Polyethylene is a polymer composed of a large number of repeating ethylene units linked together, forming a long-chain molecule, characteristic of polymers. Methane, ethanol, and acetic acid are small organic molecules that do not demonstrate the repeating unit structure typical of polymers. Therefore, they are not examples of polymers.

2. Which of the following organs is NOT directly involved in the mechanical breakdown of food?

• A. Mouth
• B. Stomach
• C. Small intestine
• D. Esophagus

Correct answer: D

Rationale: The correct answer is the esophagus (D). The esophagus is not directly involved in the mechanical breakdown of food. Its primary function is to transport food from the mouth to the stomach through peristalsis, a series of muscular contractions. The mouth is involved in the initial mechanical breakdown by chewing and mixing food with saliva. The stomach mechanically breaks down food through churning movements, and the small intestine further breaks down food through peristalsis and segmentation. Choices A, B, and C are directly involved in mechanical breakdown processes. The mouth helps in chewing and mixing food with saliva, the stomach mechanically breaks down food through churning movements, and the small intestine continues the breakdown process with peristalsis and segmentation.

3. Which of the following is the main organ responsible for producing bile?

• A. Liver
• B. Gallbladder
• C. Pancreas
• D. Stomach

Correct answer: A

Rationale: The liver is the main organ responsible for producing bile. Bile, a greenish-yellow fluid, is produced by the liver and stored in the gallbladder. Its primary function is to aid in the digestion and absorption of fats in the small intestine. When needed, the gallbladder releases bile into the small intestine to facilitate fat digestion. The pancreas produces digestive enzymes and insulin, not bile, making choice C incorrect. The stomach's primary role is to digest food through gastric juice secretion, making choice D incorrect. Therefore, the correct answer is the liver, as it is the main organ responsible for bile production.

4. What is the feedback mechanism in the endocrine system that helps maintain hormone balance?

• A. Positive feedback, where a hormone stimulates its own release
• B. Negative feedback, where a hormone suppresses its own release
• C. Cascade effect, where one hormone triggers the release of another
• D. Dual hormone system, where two hormones work together

Correct answer: B

Rationale: In the endocrine system, negative feedback is the mechanism by which hormone levels are regulated. When hormone levels reach a certain threshold, they signal the body to stop producing more of that hormone, thus maintaining a balance. Negative feedback (option B) is the correct answer as it helps in preventing overproduction of hormones by suppressing their own release. Positive feedback (option A) would lead to an excessive production of hormones, disrupting the balance. The cascade effect (option C) involves one hormone triggering the release of another but does not directly regulate hormone levels. The dual hormone system (option D) refers to two hormones working together but does not specifically address the feedback mechanism for maintaining hormone balance.

5. Which term refers to the resistance of a liquid to flow?

• A. Density
• B. Viscosity
• C. Surface tension
• D. Boiling point

Correct answer: B

Rationale: Viscosity is the term that refers to the resistance of a liquid to flow. It is a measure of how thick or sticky a fluid is and determines how easily a liquid can flow. Density (A) is a measure of how much mass is contained in a given volume and is not related to the resistance of a liquid to flow. Surface tension (C) is the property of a liquid that allows it to resist an external force due to the cohesive nature of its molecules, but it is not directly related to the resistance of a liquid to flow. Boiling point (D) is the temperature at which a liquid changes to a vapor and is not a measure of the resistance of a liquid to flow.

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