Nursing Elites

1. 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.

2. A birdbath has a hemispherical bowl with a diameter of 30cm. What is its volume?

• A. 675 cu cm
• B. 1350 cu cm
• C. 2700 cu cm
• D. 4050 cu cm

Correct answer: C

Rationale: Use half the formula for a sphere's volume: (2/3) * π * (radius)^3. Calculate the radius (15cm) and substitute: (2/3) * π * (15cm)^3 ≈ 2700 cu cm.

3. The electrical conductivity of a strong acid solution is higher than that of a weak acid solution because:

• A. Strong acids are more concentrated.
• B. Strong acids release more hydrogen ions
• C. Weak acids are better at dissolving salts.
• D. Strong acids have a lower pH.

Correct answer: B

Rationale: Strong acids completely dissociate, leading to a h

4. A reaction between an acid and a base is known as:

• A. Precipitation
• B. Neutralization
• C. Oxidation-reduction
• D. Photolysis

Correct answer: B

Rationale: When an acid and a base react, they neutralize each other's properties

5. You test a new fertilizer on two groups of plants, one with fertilizer and one without. Both groups grow at the same rate. What is the most likely explanation?

• A. The fertilizer has no effect on plant growth.
• B. The control group accidentally received some fertilizer too.
• C. Both groups received other nutrients from the soil, negating the fertilizer's effect.
• D. The test period was too short to observe any difference.

Correct answer: C

Rationale: A true control group should be identical to the test group except for the variable being tested. If both groups grew the same despite the fertilizer, it suggests external factors like soil nutrients masked any potential fertilizer effect.

6. Scientific findings are constantly evolving. This emphasizes the importance of:

• A. Unquestioning belief in established theories and models.
• B. Dogmatically adhering to the opinions of prominent scientists.
• C. Maintaining an open mind and willingness to consider new evidence.
• D. Prioritizing quick and decisive answers over careful evaluation.

Correct answer: C

Rationale: Science is a dynamic process built on continual questioning and refining of understanding. Openness to new evidence and revision of existing theories is crucial for scientific progress.

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