Nursing Elites

1. Which of the following is a common property of bases?

• A. Conductivity in aqueous solutions
• B. Sour taste
• C. Reactivity with metals to produce hydrogen gas
• D. Turns red litmus paper blue

Correct answer: D

Rationale: Bases are substances that can accept protons or donate hydroxide ions in a chemical reaction. One common property of bases is that they turn red litmus paper blue. This is a classic test to distinguish between acids (which turn blue litmus paper red) and bases. Conductivity in aqueous solutions (Option A) is a property of both acids and bases, sour taste (Option B) is a property of acids, and reactivity with metals to produce hydrogen gas (Option C) is a property of acids, not bases.

2. The muscular tube that connects the mouth to the stomach is called the:

• A. Pharynx
• B. Esophagus
• C. Trachea
• D. Larynx

Correct answer: B

Rationale: The correct answer is B: Esophagus. The esophagus is the muscular tube that connects the mouth to the stomach. It plays a crucial role in transporting food from the mouth to the stomach through peristaltic movements. The pharynx is the part of the throat that connects the mouth and nasal cavity to the esophagus and trachea. The trachea, also known as the windpipe, is responsible for carrying air to and from the lungs. The larynx, commonly known as the voice box, is involved in producing sound and protecting the trachea during swallowing. Therefore, the esophagus is specifically responsible for food transport from the mouth to the stomach.

3. A light ray travels from air (refractive index 1.00) into water (refractive index 1.33). What happens to its speed and direction?

• A. Speed increases, direction bends towards the normal.
• B. Speed increases, direction bends away from the normal.
• C. Speed decreases, direction bends towards the normal.
• D. Speed and direction remain unchanged.

Correct answer: A

Rationale: Due to the change in refractive index, the light ray bends towards the normal (water) as it slows down upon entering the denser medium.

4. Osteoporosis is a condition leading to weakened bones and increased risk of fractures. Which hormone plays a key role in bone health and is often affected in osteoporosis?

• A. Estrogen
• B. Testosterone
• C. Thyroid hormone
• D. Insulin

Correct answer: A

Rationale: Estrogen plays a crucial role in bone health by promoting the activity of bone-forming cells and inhibiting bone breakdown. In women, estrogen levels decrease significantly during menopause, leading to a higher risk of osteoporosis. This hormone helps maintain bone density and strength, making it essential for preventing bone loss and fractures. Testosterone, while important for overall health, does not have as significant of an impact on bone health as estrogen does. Thyroid hormone and insulin also have roles in the body, but they are not as directly linked to bone health as estrogen. Therefore, the correct answer is A: Estrogen.

5. A set of integers can be classified as positive, negative, or zero. Which of the following statements about multiplying positive and negative integers is ALWAYS true?

• A. The product will always be positive.
• B. The product will always be negative.
• C. The product will depend on the specific positive and negative numbers used.
• D. Positive and negative integers cannot be multiplied

Correct answer: B

Rationale: Rationale: When multiplying a positive integer by a negative integer, the product will always be negative. This is a fundamental rule of arithmetic. The sign of the product is determined by the rule that states that a positive number multiplied by a negative number results in a negative number. Therefore, the statement that the product will always be negative is always true when multiplying positive and negative integers.

6. A keystone species plays a critical role in an ecosystem because its removal would:

• A. Lead to a decrease in competition among other species
• B. Cause a slight increase in primary productivity
• C. Have a minimal impact on the overall ecosystem structure
• D. Disrupt the food web and cause cascading effects on other populations

Correct answer: D

Rationale: Rationale: Keystone species are species that have a disproportionately large effect on their environment relative to their abundance. They play a critical role in maintaining the structure and function of an ecosystem. If a keystone species is removed from an ecosystem, it can disrupt the food web by causing imbalances in predator-prey relationships. This disruption can lead to cascading effects on other populations within the ecosystem, potentially causing population declines or even extinctions. Therefore, the removal of a keystone species would have significant impacts on the overall ecosystem structure, making option D the correct answer.

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