Nursing Elites

1. When sugar is heated, it breaks down into carbon and water vapor. This is an example of a:

• A. Combination reaction
• B. Decomposition reaction
• C. Double displacement reaction
• D. Single displacement reaction

Correct answer: B

Rationale: The correct answer is B: Decomposition reaction. When sugar is heated, it undergoes a decomposition reaction where it breaks down into simpler substances, carbon, and water vapor. In a decomposition reaction, a single compound breaks down into two or more simpler substances. This process is the opposite of a combination reaction where two or more substances combine to form a new compound. Choice A, Combination reaction, is incorrect because a combination reaction involves the combination of two or more substances to form a new compound, which is the opposite of what happens when sugar breaks down. Choices C and D, Double displacement reaction and Single displacement reaction, are incorrect as they involve different mechanisms where the atoms or ions of the reactants are exchanged, which is not the case in the breakdown of sugar into carbon and water vapor.

2. Molecular clocks utilize the accumulation of mutations in DNA sequences to estimate the evolutionary divergence time between species. This method relies on the assumption that:

• A. The rate of mutation is constant across all genes and all species.
• B. Species with more morphological similarities diverged more recently.
• C. Mutations are always beneficial and contribute to increased fitness.
• D. The fossil record provides the most accurate estimates of evolutionary relationships.

Correct answer: A

Rationale: A molecular clock is a method used to estimate the time of divergence between species by measuring the accumulation of mutations in DNA sequences. This method relies on the assumption that mutations occur at a relatively constant rate over time. If the rate of mutation were not constant, it would be challenging to accurately estimate the evolutionary divergence time between species. Therefore, option A is the most appropriate choice as it aligns with the fundamental principle underlying the molecular clock hypothesis. Option B is incorrect because the assumption that species with more morphological similarities diverged more recently does not directly relate to the concept of molecular clocks and the accumulation of mutations in DNA sequences. Option C is incorrect because mutations are not always beneficial and do not always contribute to increased fitness. Mutations can be neutral or deleterious as well, and their accumulation is what is used to estimate evolutionary di

3. What do large intestines absorb?

• A. Water, sodium, and potassium ions
• B. Proteins and carbohydrates
• C. Water, vitamin K, and bile salts
• D. Vitamins A, D, E, K

Correct answer: C

Rationale: The correct answer is C. The large intestine absorbs water, vitamin K, bile salts, sodium, and chloride ions. It helps in maintaining the body's water and electrolyte balance, and also plays a role in absorbing certain vitamins and nutrients such as vitamin K. Choices A, B, and D are incorrect because proteins, carbohydrates, vitamins A, D, E, and K are primarily absorbed in the small intestine, not the large intestine.

4. What is the first number in a blood pressure reading?

• A. Diastolic pressure
• B. Mean arterial pressure
• C. Pulse rate
• D. Systolic pressure

Correct answer: D

Rationale: The correct answer is D: Systolic pressure. In a blood pressure reading, the first number represents the systolic pressure, which is the maximum pressure in the arteries during heart contraction. The second number in the reading is the diastolic pressure, which indicates the pressure in the arteries when the heart is at rest. Choices A, B, and C are incorrect because diastolic pressure, mean arterial pressure, and pulse rate are not the first numbers in a blood pressure reading.

5. Which of the following statements is true about an allergic reaction?

• A. An allergic reaction, such as hives or wheezing, results from overactive body systems such as the integumentary and respiratory systems.
• B. An allergic reaction is a result of overactive B-cells in the body that release various immunoglobulins.
• C. An allergic reaction is caused by overactive mast cells in the body, which are stimulated by Immunoglobulin E.
• D. An allergic reaction involves substances like histamine, keratin, and collagen.

Correct answer: C

Rationale: The correct answer is C. Mast cells are responsible for releasing histamine and other chemicals during an allergic response. Choice A is incorrect because hives and wheezing are symptoms of an allergic reaction, not the causes. Choice B is incorrect as B-cells are not directly involved in allergic reactions. Choice D is incorrect as keratin and collagen are not typically involved in allergic reactions, and histamine is released by mast cells.

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