Nursing Elites

1. The fossil record shows that dinosaurs with feathers existed millions of years before birds. This is evidence for

• A. Convergent evolution (unrelated organisms evolving similar traits)
• B. Divergent evolution (related organisms evolving different traits)
• C. Coevolution (two species influencing each other's evolution)
• D. The extinction of dinosaurs due to an asteroid impact

Correct answer: A

Rationale: Rationale: The fossil record indicating that dinosaurs had feathers before birds suggests convergent evolution. Convergent evolution occurs when unrelated organisms independently evolve similar traits to adapt to similar environmental pressures. In this case, both dinosaurs and birds developed feathers for flight or insulation purposes, even though they are not closely related. This evidence supports the concept of convergent evolution rather than divergent evolution, coevolution, or the extinction of dinosaurs due to an asteroid impact.

2. Which element is present in household bleach and has disinfectant properties?

• A. Sodium
• B. Chlorine
• C. Fluorine
• D. Iodine

Correct answer: B

Rationale: Chlorine's oxidizing ability makes it effective in killing bacteria and other microorganisms.

3. The energy released in nuclear fusion originates from:

• A. The fission of heavy nuclei
• B. The binding energy released during the fusion of light nuclei
• C. Electronic transitions within atoms
• D. Matter-antimatter annihilation

Correct answer: B

Rationale: The correct answer is B: 'The binding energy released during the fusion of light nuclei.' Nuclear fusion is the process where light nuclei combine to form a heavier nucleus, releasing energy in the form of binding energy. This energy comes from the conversion of mass into energy as per Einstein's famous equation E=mc^2. In contrast, option A refers to nuclear fission, where heavy nuclei split into lighter nuclei, releasing energy. Option C is related to atomic energy levels, and option D involves the complete conversion of matter into energy, not specific to nuclear fusion. Therefore, the energy released in nuclear fusion originates from the binding energy released during the fusion of light nuclei.

4. Unlike the circulatory system, the lymphatic system does not have a pump. How does lymph move through the lymphatic vessels?

• A. By the pumping action of the heart
• B. Due to muscle contractions and breathing movements
• C. Through one-way valves within the vessels
• D. All of the above

Correct answer: D

Rationale: The correct answer is D, 'All of the above.' Unlike the circulatory system which relies on the heart's pumping action, the lymphatic system lacks a central pump. Lymph moves through lymphatic vessels primarily due to muscle contractions and breathing movements that squeeze the vessels, helping propel the lymph forward. Additionally, one-way valves within the lymphatic vessels prevent the backward flow of lymph, ensuring it moves in the right direction. Therefore, all three mechanisms - heart pumping, muscle contractions, and one-way valves - work together to facilitate the movement of lymph through the lymphatic system.

5. Two identical balls, one made of clay and the other made of steel, are dropped from the same height. Which ball reaches the ground first, neglecting air resistance?

• A. The clay ball due to its lower density
• B. The steel ball due to its higher density
• C. Both balls reach the ground simultaneously
• D. It depends on the initial velocities of the balls

Correct answer: C

Rationale: In a vacuum (neglecting air resistance), the acceleration due to gravity is constant for all objects regardless of their mass or composition. This means both balls will experience the same acceleration and reach the ground at the same time.

6. Half-life refers to the characteristic time it takes for:

• A. Radioactive intensity to completely disappear
• B. The number of neutrons in a nucleus to double
• C. The number of protons in a nucleus to change
• D. An isotope to decay by half of its initial quantity

Correct answer: D

Rationale: The correct answer is D: An isotope to decay by half of its initial quantity. The half-life of a substance is the time it takes for half of the initial quantity of radioactive atoms to decay. This is a characteristic property of each radioactive isotope and is used to determine the rate of decay of a substance. Option A is incorrect because radioactive intensity does not completely disappear in half-life, it only decreases by half. Options B and C are unrelated to the concept of half-life and do not accurately describe its definition.

Similar Questions