Nursing Elites

1. What happens to the speed of a sound wave when it travels from air to water?

• A. It increases because water is denser.
• B. It decreases because water is denser.
• C. It remains the same.
• D. Speed depends on the frequency, not the medium.

Correct answer: B

Rationale: When a sound wave travels from air to water, the speed of sound decreases because sound travels faster in denser mediums. Water, being denser than air, causes the speed of sound to slow down. Choice A is incorrect because sound travels faster in denser mediums, so the speed would not increase. Choice C is incorrect because the speed of sound changes when transitioning between different mediums. Choice D is incorrect because while frequency does affect sound, the medium it travels through also plays a significant role in determining the speed of sound.

2. How is the density of a substance calculated?

• A. Mass / Volume
• B. Volume / Mass
• C. Mass x Volume
• D. None of the above

Correct answer: A

Rationale: The density of a substance is calculated by dividing the mass of the substance by its volume. The formula for density is Density = Mass / Volume. This calculation allows us to determine how much mass is present in a given volume of a substance, making option A the correct choice. Choice B (Volume / Mass) is incorrect because density is defined as mass per unit volume, so mass should be the numerator. Choice C (Mass x Volume) is incorrect as this would result in a different unit of measurement and not represent density. Choice D (None of the above) is incorrect as there is a specific formula for calculating density, which is mass divided by volume.

3. Which organ stores and concentrates bile?

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

Correct answer: B

Rationale: The correct answer is B: Gallbladder. The gallbladder is the organ that stores and concentrates bile produced by the liver. Bile is essential for the digestion of fats in the small intestine. The liver produces bile, which is then stored and concentrated in the gallbladder until it is released into the small intestine when needed. Choices A, C, and D are incorrect because the liver produces bile, the pancreas produces digestive enzymes, and the stomach is primarily involved in the digestion of food through acid secretion and mechanical processes, not in storing bile.

4. Which of the following organs functions as both an endocrine and exocrine gland?

• A. The kidney
• B. The spleen
• C. The pancreas
• D. The stomach

Correct answer: C

Rationale: The pancreas is the correct answer as it functions as both an endocrine and exocrine gland. The endocrine function involves secreting insulin and glucagon into the bloodstream to regulate blood sugar levels, while the exocrine function involves releasing digestive enzymes into the small intestine to aid in digestion. The kidney (Choice A) primarily functions in the excretory system by filtering blood and producing urine. The spleen (Choice B) is involved in the immune system and blood storage but does not have endocrine or exocrine functions. The stomach (Choice D) is mainly an organ of the digestive system, secreting gastric juices to aid in digestion, but it does not have a dual endocrine and exocrine function like the pancreas.

5. What role does DNA play in evolution?

• A. It stores genetic information that can be passed on to offspring.
• B. It allows for mutations that can introduce new variations.
• C. It regulates the expression of genes that influence traits.
• D. All of the above

Correct answer: D

Rationale: A) DNA stores genetic information that is passed on from parents to offspring through the process of reproduction. This genetic information contains instructions for the development and functioning of an organism. It serves as the hereditary material that carries the blueprint for an organism's traits and characteristics, allowing for the transmission of genetic information from one generation to the next. B) DNA can undergo mutations, which are changes in the genetic sequence. These mutations can introduce new variations in the DNA, leading to genetic diversity within a population. These variations are essential for natural selection and adaptation to changing environments. C) DNA plays a crucial role in regulating the expression of genes. Gene expression determines which proteins are produced in an organism, influencing its traits and characteristics. By controlling gene expression, DNA contributes to the development and maintenance of an organism's traits. D) Therefore, DNA is involved in all of the above processes, making it a key factor in evolution by driving genetic variation, inheritance, and gene expression. The interplay of these functions allows for the diversity and adaptation of species over time, shaping the evolutionary process.

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