Nursing Elites

1. Which of the following is NOT a primary producer in an ecosystem?

• A. Grass
• B. Deer
• C. Algae
• D. Mushroom

Correct answer: B

Rationale: Rationale: - A) Grass: Grass is a primary producer because it can photosynthesize and convert sunlight into energy, making it the base of the food chain. - B) Deer: Deer are consumers that feed on primary producers like grass, so they are not primary producers themselves. - C) Algae: Algae are primary producers that can photosynthesize and produce energy from sunlight. - D) Mushroom: Mushrooms are decomposers that break down organic matter, so they are not primary producers.

2. What is the role of surfactant in the respiratory system?

• A. To trap dust particles
• B. To increase lung compliance
• C. To produce mucus
• D. To generate oxygen during respiration

Correct answer: B

Rationale: The correct answer is B: 'To increase lung compliance.' Surfactant is a substance produced by the alveolar cells in the lungs that reduces surface tension within the alveoli. This helps to prevent the alveoli from collapsing, making it easier for the lungs to expand and contract during breathing. This action increases lung compliance, which is the ease with which the lungs can be inflated. Trapping dust particles (A) is the role of mucus and cilia in the respiratory system. Surfactant does not produce mucus (C) but rather acts to reduce surface tension. Generating oxygen (D) is the function of the respiratory system as a whole through the process of respiration, and surfactant does not play a direct role in this process.

3. Which type of reaction is represented by the equation A + B → AB?

• A. Synthesis
• B. Decomposition
• C. Single Replacement
• D. Double Replacement

Correct answer: a

Rationale: Synthesis reactions involve the combination of two or more substances to form a new compound.

4. What is the name of the structure that packages DNA in eukaryotic cells?

• A. Nucleosome
• B. Chromatin
• C. Histone
• D. Centromere

Correct answer: A

Rationale: Rationale: - A nucleosome is the basic structural unit of DNA packaging in eukaryotic cells. It consists of DNA wrapped around a core of histone proteins. - Chromatin refers to the complex of DNA and proteins found in the nucleus of a eukaryotic cell, including nucleosomes. - Histones are the proteins around which DNA is wrapped to form nucleosomes. - Centromere is a region of a chromosome where the two sister chromatids are joined and to which spindle fibers attach during cell division.

5. Which property of a substance refers to its ability to undergo a chemical change and form new substances?

• A. Density
• B. Mass
• C. Reactivity
• D. Volume

Correct answer: c

Rationale: Reactivity refers to a substance's ability to undergo chemical changes, forming new substances with different properties.

6. What is the main difference between a nuclear reactor and a nuclear bomb?

• A. Reactors use enriched uranium, while bombs use natural uranium.
• B. Reactors have controlled chain reactions, while bombs have uncontrolled chain reactions.
• C. Reactors generate electricity, while bombs cause explosions.
• D. Reactors use moderators, while bombs don't.

Correct answer: B

Rationale: The key difference lies in the control of the fission chain reaction. Reactors have controlled reactions for energy generation, while bombs have rapid, uncontrolled reactions creating explosions.

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